The Open Collections website will be unavailable July 27 from 2100-2200 PST ahead of planned usability and performance enhancements on July 28. More information here.

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Phosphorus release from dairy manure Pan, Szu-Hua 2005

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Notice for Google Chrome users:
If you are having trouble viewing or searching the PDF with Google Chrome, please download it here instead.

Item Metadata

Download

Media
831-ubc_2005-0296.pdf [ 9.07MB ]
Metadata
JSON: 831-1.0092007.json
JSON-LD: 831-1.0092007-ld.json
RDF/XML (Pretty): 831-1.0092007-rdf.xml
RDF/JSON: 831-1.0092007-rdf.json
Turtle: 831-1.0092007-turtle.txt
N-Triples: 831-1.0092007-rdf-ntriples.txt
Original Record: 831-1.0092007-source.json
Full Text
831-1.0092007-fulltext.txt
Citation
831-1.0092007.ris

Full Text

PHOSPHORUS RELEASE FROM DAIRY MANURE by SZU-HUA PAN B . S c , The N a t i o n a l C h i a o T u n g Un ive r s i t y , 1999 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (RESOURCE MANAGEMENT AND ENVTRONMENTAL STUDIES) THE UNIVERSITY OF BRITISH COLUMBIA A p r i l 2005 © S z u - H u a Pan , 2005 A B S T R A C T The m o l y b d e n u m blue methods were used to determinate phosphate concentrat ion o f l i q u i d dairy manure. V a r y i n g l i q u i d dairy manure/deionized water ratios revealed that there exis ted a posi t ive effect o f d i lu t ion by de ion ized water o n the measured manure ortho-P concentration. Several chemica ls such as sod ium bicarbonate, sod ium bisulf i te , hydroch lor ic ac id , hydrogen peroxide etc. fa i led to e l iminate the interference caused b y the u n k n o w n c o m p o u n d i n the dai ry manure. The recovery o f phosphorus f rom an imal manures w i l l be an important step i n the overa l l management and sustainabil i ty o f phosphorus use. The combined chemica l s /mic rowave treatment o f r aw dai ry manure was developed as part o f the studies for enhancing the recovery o f phosphorus f rom an imal wastes. U p to 8 6 % o f total phosphate c o u l d be released into solu t ion w i t h a total o f ten minutes o f m i c r o w a v e treatment. A n efficient approach was developed for faci l i ta t ing phosphorus release f rom dairy manure at ambient temperature. U p to 8 0 % o f the total phosphate c o u l d be released from dai ry manure. i i T A B L E O F C O N T E N T S A B S T R A C T ii T A B L E O F C O N T E N T S iii L I S T O F T A B L E S • v L I S T O F F I G U R E S v i A C K N O W L E D G E M E N T S v i i i 1 I N T R O D U C T I O N 1 1.1 Phosphorus P roduc t ion i n Canad ian L i v e s t o c k M a n u r e 1 1.2 A g r i c u l t u r a l Intensification i n the L o w e r Fraser V a l l e y ( L F V ) 1 2 O B J E C T I V E S 3 3 L I T E R A T U R E R E V I E W 4 3.1 Phosphorus Resource 4 3.1.1 The R o l e o f Phosphorus i n Nature 4 3.1.2 A g r i c u l t u r a l Phosphorus and Eut rophica t ion 5 3.1.3 Phosphate Sustainabi l i ty 6 3.1.4 Phosphorus i n Wastewater 7 3.2 A n i m a l M a n u r e 8 3.2.1 Nut r ien t Content i n A n i m a l Manures 8 3.2.2 Phosphorus F o r m s i n A n i m a l M a n u r e s 9 3.2.3 A n i m a l M a n u r e and Env i ronmen ta l Impacts 10 3.3 Phosphorus Recovery f rom M a n u r e . .11 3.3.1 Phosphorus Recove ry Processes 11 4 M A T E R I A L S & M E T H O D S 13 4.1 Source o f D a i r y M a n u r e 13 4.2 M a n u r e P Character izat ion 15 4.3 C h e m i c a l and/or P h y s i c a l Pre-treatment Process 16 4.3.1 R o o m Temperature Pre-treatment Process 16 4.3.2 M i c r o w a v e Pre-treatment Process ( A t Preset Temperatures) 18 5 R E S U L T S & D I S C U S S I O N S 21 5.1 D a i r y M a n u r e P Character izat ion 21 i i i 5.1.1 p H 21 5.1.2 To ta l So l ids 22 5.1.3 T P Concentra t ion 23 5.1.4 Or tho-P Concentra t ion 24 5.1.4.1 V e r i f i c a t i o n o f Or tho-P Interference 25 5.1.4.2 Au tomated A s c o r b i c R e d u c t i o n M e t h o d 26 5.1.5 Tests o f Interference E l i m i n a t i o n 27 5.1.5.1 F i l t ra t ion & Deco lo r i z a t i on 27 5.1.5.2 Extract ions 29 5.2 M a n u r e Pre-treatment Process 33 5.2.1 R o o m Temperature Pre-treatment Process 34 5.2.2 M i c r o w a v e Pre-treatment Process 37 5.3 Resul ts Summary 44 6 C O N C L U S I O N S 47 7 R E C O M M E N D A T I O N S F O R F U T U R E S T U D I E S 48 R E F E R E N C E S 49 A P P E N D I X A C H A R A C T E R I S T I C S O F D A I R Y M A N U R E 54 A P P E N D I X B O R T H O - P S T A N D A R D A D D I T I O N I N D A I R Y M A N U R E 55 A P P E N D I X C I N T E R F E R E N C E E L I M I N A T I O N T E S T S 56 A P P E N D I X D R O O M T E M P E R A T U R E P R E - T R E A T M E N T P R O C E S S 57 A P P E N D I X E M I C R O W A V E P R E - T R E A T M E N T P R O C E S S 58 i v L I S T O F T A B L E S Table 1. Nutr ient ava i lab i l i ty f rom l ives tock waste b y minera l species 3 8 Tab le 2. Resul ts summary o f manure p characterization and pre-treatment processes. . . . 45 Table A - l . p H & total so l ids i n l i q u i d dairy manure 54 Table A - 2 . To ta l phosphate concentrat ion i n l i q u i d dai ry manure 54 Tab le A - 3 . Or tho -P concentrat ion i n l i q u i d da i ry manure 54 Table B - l . Extent o f recovery o f the added quantity o f ortho-P standards 55 Table B - 2 . T h e data compar i son o f ortho-P standard addi t ion 55 Tab le C - l . Deco lo r i z a t i on o f dairy manure sample by activated charcoal 56 Table C - 2 . Or tho-P concentrat ion o f dairy manure extracted w i t h N a H C O a / H C l 56 Table C - 3 . Or tho-P concentrat ion i n the so lu t ion extracted w i t h NaHS0 3 /HCl+NH4F.. . 56 Table C - 4 . Or tho-P concentrat ion i n the solu t ion induced b y H2O2 56 Table D - l . Or tho-P concentration i n the solu t ion w i t h m a n u r e / F b A (v/v) = 20:1 57 Table D - 2 . Or tho-P concentrat ion i n the solu t ion w i t h manure/H202 (v/v) = 5:1 57 Tab le D - 3 . Or tho-P concentrat ion i n the so lu t ion induced by combined H2SO4/H2O2.... 57 Table E - l . Or tho-P concentrat ion i n the solu t ion induced by one stage m i c r o w a v e treatment wi thout chemica l addi t ion 58 Table E - 2 . Or tho-P concentrat ion i n the so lu t ion induced b y combined H202/one stage mic rowave treatment 59 Table E - 3 . Orfho-P concentration i n the so lu t ion induced by combined FfeSOVone stage mic rowave treatment 60 Table E - 4 . Or tho-P concentrat ion i n the so lu t ion induced b y combined H2S04/H202/two stages mic rowave treatment 61 Tab le E - 5 . Or tho -P concentrat ion i n the so lu t ion induced b y combined F k O j / E b S O V t w o stages mic rowave treatment 62 L I S T O F F I G U R E S Figure 1. M a i n use o f phosphate 6 F igure 2 . Phosphorus input and eutrophicat ion 7 F igure 3. Exper iment f l o w chart \ 14 F igure 4. D i l u t i o n preparation o f manure samples 15 Figure 5. Rela t ionships o f p H o f manure/deionized water (v/v) to stored t ime i n dairy manure 21 F igure 6. Rela t ionships o f T S concentrat ion o f manure/deionized water (v/v) to stored t ime i n dairy manure 22 F igure 7. Rela t ionship o f T P concentration to stored t ime i n dairy manure 23 F igure 8. Re la t ionsh ip o f manure/deionized water (v/v) and ortho-P concentrations i n dairy manure (mean o f ten observations) 24 Figure 9. Re la t ionsh ip o f manure/deionized water (v/v) to ortho-P concentrations i n dairy manure w i t h standard addi t ion 26 Figure 10. Re la t ionsh ip o f manure/deionized water (v/v) to ortho-P concentrat ion i n dai ry manure w i t h decolor iza t ion 28 Figure 11. Rela t ionships o f manure/deionized water (v /v) w i t h ortho-P concentrations i n dairy manure w i t h extractant o f H C l / N a H C C h 29 Figure 12. Re la t ionsh ip o f manure/deionized water (v/v) to ortho-P concentrations i n dairy manure w i t h extractant o f NaHSC»3 30 F igu re 13. Re la t ionsh ip o f manure/deionized water (v /v) to or tho-P concentrations i n dairy manure w i t h extracting reagent - H C I + NH4F 31 F igure 14. Rela t ionships o f manure/deionized water (v/v) to ortho-P concentrations i n dai ry manure w i t h H2O2.. 32 F igure 15. Re la t ionsh ip o f react ion t ime to ortho-P concentrations i n dai ry manure w i t h H2O2 ox ida t ion (mean o f four observations) 35 F igure 16. Re la t ionsh ip o f reaction t ime to ortho-P concentrations i n dairy manure w i t h combined H2SO4/H2O2 (mean o f four observations) 36 F igure 17. Re la t ionsh ip o f temperature o n ortho-P concentrations i n dairy manure w i t h m ic rowave treatment on ly (mean o f fifteen observations) 37 v i Figure 18. Rela t ionsh ip o f temperature o n ortho-P concentrations i n dairy manure w i t h A O P ' s (mean o f fifteen observations) 39 F igure 19. Rela t ionship o f temperature to ortho-P concentrations i n dairy manure w i t h ^ S O V m i c r o w a v e process (mean o f fifteen observations) 41 F igure 20 . Re la t ionsh ip o f temperature o n or tho-P concentrations i n dai ry manure w i t h combined H2S04/H2CVmicrowave process (mean o f twelve observations) 43 v i i A C K N O W L E D G E M E N T S The author w o u l d l i ke to express her sincere appreciat ion and gratitude to her supervisor, D r . K . V i c t o r L o , for his guidance and encouragement throughout the preparation o f this thesis. The author w o u l d l i ke to thank to D r . Hans E . Schreier, D r . L e s M . L a v k u l i c h , D r . Kenne th J . H a l l , and D r . A n t h o n y L a u for their support and advice as w e l l . Thanks are also due to D r . P i n g L i a o and M s . C a r o l A . D y c k , for their advice and assistance for process operat ion i n the laboratory. T h e author also wishes to thank her f a m i l y for their support and encouragement throughout the study. v i i i 1 I N T R O D U C T I O N 1.1 Phosphorus Production in Canadian Livestock Manure Canad ian l ives tock produced an estimated 214 m i l l i o n k i lograms o f phosphorus i n their manure i n 1996 (Statistics Canada, 2001) . A b o u t 5 1 % o f this manure was produced b y beef cattle, f o l l owed b y hogs (21%), da i ry cows (13%), poul t ry (8%), calves (5%), horses (2%) and sheep (less than 1%). T h i s indicates that the quantities o f phosphorus potent ial ly avai lable for recovery and r ecyc l i ng i n an ima l manures are s ignif icant ly greater than those i n m u n i c i p a l sewage. T h e amount o f phosphorus produced i n Canad i an l ives tock manure is mapped by sub-basin area. There are 22 sub-basins w i t h h i g h concentrations o f phosphorus (over 5 k i log rams per hectare) (Statistics Canada, 2001) . O f the 22 sub-basins that fa l l into the highest category, o n l y seven were located outside o f Ontar io and Quebec. Those seven were located i n the L o w e r Fraser V a l l e y o f southern B r i t i s h C o l u m b i a , central and southern Albe r t a , southern M a n i t o b a , Pr ince E d w a r d Is land and N o v a Scot ia . The highest concentrations o f phosphorus generated were general ly located near areas w i t h h i g h agricul tural act ivi t ies. 1.2 Agricultural Intensification in the Lower Fraser Valley (LFV) Intensification o f l ives tock product ion i n the rural-urban fringe area o f V a n c o u v e r is becoming o f increasing concern, because agriculture is n o w considered the largest contributor to nonpoint source po l lu t ion . Schreier et al (2003) reported that overa l l the cattle, p i g and sheep numbers have dec l ined i n the L F V but the number o f da i ry c o w s and chickens continue to increase. C h i c k e n product ion increases have been par t icular ly dramatic w i t h a 5 2 % increase between 1996 and 2001 . The L F V has n o w the largest number o f da i ry cows/per fa rm i n Canada and there has been a 7 8 % increase i n number o f chickens/ farm over the past 10 years, a 7 5 % increase i n goat numbers/farm, a 7 0 % increase i n dai ry cows and a 5 0 % increase i n p i g 1 n imbe r s / f a rm (Schreier et al., 2003) . T h i s indicates that agricul tural intensif icat ion is o n a rapid rise i n the L F V , and h i g h agricul tural intensif icat ion and h igh an imal s tocking density w i l l cause nutrient surplus problems. B a s e d o n 1991 census data, B r i s b i n (1995) estimated that manure-P product ion f rom a l l l ives tock i n the L o w e r Fraser V a l l e y was equivalent to 84 k g P ha" 1 o f land i n agricul tural product ion ( inc lud ing land i n annual- and perennial-crop product ion and improved and un improved pasture). F o r the L o w e r Fraser V a l l e y as a whole , ni trogen, phosphorus and potass ium appl ica t ion o n agricul tural l and exceed the crop requirements by a significant marg in . 5 0 % o f a l l areas showed an increase i n surplus N and P over the past 10 years (Schreier et al, 2003) . 6 5 % o f the areas i n the L o w e r Fraser V a l l e y had surplus ni t rogen applicat ions i n excess o f 100 kg/ha/year and phosphorus surplus applicat ions were i n excess o f 50 kg/ha/year (Schreier et al, 2003) . The surplus ni t rogen applicat ions have increased i n 4 5 % o f the areas between 1996 and 2001 and the surplus phosphorus applicat ions have increased i n 7 5 % o f the areas (Schreier et al., 2003) . These values are above what is needed by the plants and are a threat to the freshwater resources i n each surplus area result ing i n eutrophication and water qual i ty deterioration. 2 2 OBJECTIVES The L F V has n o w the largest number o f dairy cows/per fa rm i n Canada and the cattle dis t r ibut ion o f L F V i n year 2001 is 118,769 total ly (Schreier et al, 2003) . These numbers c lear ly indicate that agricul tural intensif icat ion is a rise. The dai ry c o w o f per 1000 k g ( l ive an imal mass) can produce 86 ± 17 k g o f fresh manure per day ( A S A E Standards, 2003) . These large wastes vo lumes are considered a p rob lem. N and P excretions by dai ry c o w s var ied dramat ica l ly b y the l eve l o f N and P intakes (Morse et al, 1992; T o m l i n s o n et al, 1996). It is important to manage dairy manure P appropriately by recover ing phosphorus. Charac ter iz ing manure P i s an important step to better understand the chemistry i n v o l v e d and it w i l l further enhance our capabi l i ty i n manag ing manure P for reduced water po l lu t ion . Recove ry o f phosphorus f rom an imal manures requires some k i n d o f pre-treatment processes i n order to render the phosphorus soluble into solut ion. The purpose o f this study was to develop a method for op t imal extract ion o f P f rom dairy manure b y us ing chemica l and/or phys i ca l pretreatment processes. T h e objectives o f this study were 1) to characterize phosphorus i n dai ry manure and 2) to op t imize phosphorus release from dai ry manure b y us ing chemica l and/or phys i ca l pre-treatment processes. 3 3 L I T E R A T U R E R E V I E W 3.1 Phosphorus Resource 3.1.1 The Role of Phosphorus in Nature Phosphorus is the eleventh most abundant element i n the li thosphere, essential to a l l l i v i n g organisms (Becker , 1989). It is w i d e l y used i n c e l l structure as w e l l as c e l l function. In particular, a longside ni trogen, it is one o f the m a i n plant nutrients. O w i n g to its relative react ivi ty, it general ly is associated w i t h c a l c i u m (Ca) , sod ium (Na) , f luor ine (F) , ch lor ide (CI) , metals such as i r o n (Fe) , a l u m i n u m ( A l ) , magnes ium ( M g ) , heavy metals, for example c a d m i u m ( C d ) , radionucl ide l i k e u ran ium ( U ) etc. In nature, phosphorus a lways occurs combined w i t h o x y g e n and other elements, fo rming rock phosphates. Phosphorus resources occur i n some sedimentary and igneous rocks , k n o w n as phosphate rock. Deposi ts o f phosphate rock occur i n many places i n the Ear th ' s crust but h i g h grade reserves, workable for c o m m e r c i a l exploi ta t ion are geographical ly l im i t ed . Phosphorus input into natural systems comes o n l y f rom the weathering o f certain rocks and is compara t ive ly rare. Because o f the l o w so lub i l i ty , phosphorus is usual ly deficient i n soi ls and the sustainabil i ty o f t radi t ional agriculture is dependent o n the phosphorus cyc le . The phosphorus cyc le has largely been replaced b y a l inear throughput system: phosphates are extracted f rom a non-renewable resource (phosphate rock) appl ied to l and taken up b y plants, pass through crops, animals and man , and end up either i n l and f i l l o f r aw or incinerated sewage sludge or i n rivers and the sea i f sewage or an ima l wastes are not adequately treated. Compara t ive ly l i t t le is restored to agricul tural land. O f the estimated 150 m i l l i o n tones per year o f phosphorus (P) currently extracted and processed g loba l ly , 8 5 % is used i n agriculture as fert i l izers and feed concentrates ( C E E P , 1998). Domes t i c farm animals t yp i ca l ly excrete 7 0 % o f P intake (Barnett, 1994). Phosphates f rom ferti l izers and manure m a y also b u i l d up i n agricul tural so i l , i n some 4 circumstances towards or beyond saturation levels . Part o f the appl ied phosphates m a y tend to run o f f into surface water rather than be ing retained i n the s o i l and crops. W h e n phosphates get in to aquatic system, it w i l l cause eutrophication. 3.1.2 Agricultural Phosphorus and Eutrophication Phosphorus (P) is an essential element for plant and an ima l growth and its input has l o n g been recognized as necessary to main ta in profitable crop and an ima l product ion. Phosphorus inputs can also increase the b i o l o g i c a l p roduct iv i ty o f surface waters b y algae growth leading to accelerate eutrophication. Eut rophica t ion o f most fresh water around the w o r l d is accelerated by P inputs (Schindler , 1977; Sharpley et al, 1994). Eut rophica t ion is the natural ag ing o f lakes or streams brought o n by nutrient enrichment. T h i s process can be greatly accelerated b y human act ivi t ies that increase nutrient l oad ing rates to water. The result o f eutrophicat ion is often caused w h e n the balance o f product ion and consumpt ion i n the food cha in is disturbed and, i n most cases, this leads to algae becoming the dominant fo rm o f l ife i n the water. In the wors t cases, algae proliferate, w h i c h is no longer contro l led b y higher levels i n the food cha in . T h i s m a y lead to a decl ine i n other water plants, par t icular ly bot tom g r o w i n g plants w h i c h fa i l to compete for l ight i n the turbid-water c o l u m n . T h i s loss i n plant d ivers i ty can also lead to a shift i n f i sh species that m a y further affect the operating o f the food cha in . In the most extreme cases, t ox ic algae m a y be formed and water m a y become deoxygenated, leading to f ish k i l l s . Eut rophica t ion has been ident i f ied as the m a i n cause o f impa i red surface water qual i ty ( U . S . Env i ronmen ta l Protect ion A g e n c y 1996). Eut rophica t ion restricts water use for fisheries, recreation, industry, and d r ink ing because o f increased growth o f undesirable algae and aquatic weeds and the o x y g e n shortages caused b y their death and decomposi t ion . Assoc ia t ed per iodic surface b looms o f cyanobacter ia (blue-green algae) occur i n dVinking water supplies and m a y pose a serious health hazard to animals and humans. 5 3.1.3 Phosphate Sustainability Current major use o f P is i n ferti l izers, P reuse and r ecyc l ing are o f great importance for sustaining profitable agricul tural product ion i n the l ong te rm (Abe l son , 1999). A r o u n d 8 0 % o f phosphates produced indust r ia l ly i n the w o r l d are used i n ferti l izers, w i t h a further 5 % being used i n an imal feeds. These phosphates are manufactured f rom phosphate-containing rock m i n e d from deposits i n several countries. O v e r 30 countries are currently producing phosphate rock for use i n domest ic markets and/or international trade. The w o r l d ' s top 12 produc ing countries account for nearly 9 5 % o f the w o r l d ' s total phosphate product ion. The three major p roduc ing countries, the U S A , C h i n a and M o r o c c o , currently produce approximate ly two thirds o f g loba l phosphate product ion. The phosphate rock is the commerc i a l phosphate source. It is p r imar i ly i n the c a l c i u m phosphate forms, but contains a w i d e range o f impuri t ies . The annual g loba l product ion o f phosphate is around some 40 m i l l i o n tones o f P2O5, extracted f rom roughly 150 m i l l i o n tons o f phosphate rock concentrate (Greaves et al, 1999). O v e r a l l , minera l ferti l izers account for approximate ly 8 0 % o f phosphates used w o r l d w i d e w i t h the balance d i v i d e d between detergents (12%), an imal feeds (5%) and special ty applications (3%), i.e. food grade, metal treatment etc. (See F igure 1). Figure 1. Main use of phosphate. Natura l ore deposits that contain large amounts o f P are rare, and they are be ing dissipated expedi t iously ( A b e l s o n , 1999). Estimates o f the Earth's phosphate reserves vary considerably but most experts expect them to last no more than one hundred years at 6 current exploi ta t ion rates (Dr ive r , 1999). H o w e v e r , it is certainly true that the highest qual i ty reserves are be ing depleted rap id ly and the w a y w e currently use phosphate does not agree w i t h the pr inc ip les o f sustainabili ty. Based o n best avai lable estimates, a "most probable" scenario is that 60 per cent o f the w o r l d ' s k n o w n phosphate reserves w i l l be depleted w i t h i n 60 years. I f even s l ight ly higher phosphate usage occurs (e.g. a 3 % growth rate vs . current growth rates o f 1.5%), the entire supply o f c o m m e r c i a l l y workab le , phosphate rock w i l l be depleted even earl ier (Dr ive r , 1999). A s the w o r l d ' s supply o f phosphate rock, the major source o f chemica l fert i l izers, is depleted, prices w i l l increase, leading to supply shortages. Therefore, there are very good reasons to consider the recovery, r ecyc l ing and reuse o f phosphate f rom waste. The impact o f the d i m i n i s h i n g w o r l d supply o f phosphorus resources can be m i n i m i z e d . T o take steps to ga in some measure o f l ong term phosphate sustainabili ty i s o f considerable interest to the phosphorus industry. 3.1.4 Phosphorus in Wastewater M u n i c i p a l and agriculture waste are two major sources o f phosphorus (See F igure 2). Agr i cu l tu re represents the highest share among the phosphate fert i l izer consumers. The quantities o f potent ial ly avai lable P for recovery and r ecyc l ing i n an imal manures are s ignif icant ly greater than those i n m u n i c i p a l sewage. F o r example , i n the U n i t e d K i n g d o m , 200,000 tones o f phosphorus are generated b y an imal manures and slurries, and this result i n a major disposal p rob lem (Dr iver , 1999). Run-off from agricultural land Effluent containing detergent or partially treated sewage Figure 2. Phosphorus input and eutrophication. Wastewater discharges o f ni trogen and phosphorus to the environment are undesirable because these nutrients accelerate eutrophication. Further problems occur because certain forms o f ni t rogen (ammonia , nitrite, and nitrate) are t ox i c to aquatic l i fe or m a y lead to diseases i n those w h o d r ink water contaminated w i t h these compounds . Despi te the environmental and health benefits o f l i m i t i n g nutrient discharges, there is a con t inu ing need to supply ni trogen and phosphorus to agriculture and industry. Thus , development o f treatment methods that facilitate recovery o f nutrients f rom wastewater w i l l improve the sustainabil i ty o f these v i t a l activit ies. 3.2 Animal Manure 3.2.1 Nutrient Content in Animal Manures Table 1. Nutrient availability from livestock waste by mineral species3. Nutrients available to crops per animal unit (kg/yr) Species Nitrogen Phosphate1 (P 20 5) Potash*(K20) Dairy 12-18 15-36 36-72 Beef Fed Beef 9-45 10-45 15-52 Cow-calf 36-45 39-45 45-52 Swine Fed swine 1-5 4-8 5-8 Swine breeding 3-14 3-6 7-10 Poultry Layer 0.22-0.29 0.37-0.39 0.22-0.23 Broiler 0.16-0.19 0.19-0.20 0.24 Turkey 0.46-0.55 0.64-0.68 0.64 Sheep Fed lambs 1.8-2.4 0.9-1.2 2.8-3.5 Ewes and lambs 2.9-3.8 1.4-2.0 4.3-5.8 " Ranges are attributable to differences in handling, storage and application technology. 'Phosphate (P2O5) = 2.27y.P.2Potash (K20) = 1.2 xK. ( F r o m W h i t e and Forster, 1978). Tab le 1 gives estimates o f the N , P and K concentrations i n fresh manure from different l ives tock species and poul try. A z e v e d o and Stout (1974) and Whetstone et al. (1974) 8 reported that the compos i t i on o f manure depends o n the an imal , its stage o f g rowth and its feed. H a y s and Swenson (1970) indicated that P i n ruminant manures is general ly lower than i n poul t ry or swine manures because ruminants can extract o rgan ica l ly -bound phosphorus f rom plant feeds. P is excreted largely i n the feces o f the different an ima l species; on ly smal l amounts are found i n the urine (Barnett, 1994). 3.2.2 Phosphorus Forms in Animal Manures M a n u r e contains organic and inorganic phosphate compounds . The inorganic P in i t i a l ly is quite soluble and avai lable ; however , w h e n it comes i n contact w i t h so i l , var ious reactions beg in to take place. Those reactions make phosphate less soluble i n water and less avai lable to plants. T h e rates and products o f these reactions are dependent o n so i l p H , moisture, and the minerals already present i n the s o i l . C h e m i c a l ident if icat ion o f organic P forms i s diff icul t due to the h i g h l y reactive nature o f the tr ivalent PO4 " group and its propensity towards hydro lys i s f rom the organic fo rm dur ing extraction and ident i f icat ion procedures. Phosphorus i n the l i q u i d fractions o f manure has t radi t ional ly been grouped into total P (P t ) , inorganic P (Pj) and organic P ( P 0 ) (Ormaza-Gonzalezet al, 1996). Inorganic P is determined us ing the methods o f M u r p h y & R i l e y ( M u r p h y et al., 1962) w h i c h re ly o n a react ion between the PO4 group and molybdate under ' su i tab ly ' ac id ic condi t ions. S u c h condi t ions are l i k e l y to promote the dissocia t ion o f w e a k l y bound P f rom both organic and inorganic complexes w h i c h m a y lead to the overest imat ion o f Pj . Hence , a more accurate descr ipt ion o f P determined i n this w a y might be reactive P ( R P ) or molybdate relative P ( M R P ) . T o t a l P is determined i n the same w a y , f o l l o w i n g hydro lys i s and d issocia t ion o f a l l organic and inorganic P complexes by K j e l d a h l digest ion method. Organ ic P is estimated as the difference between P t and P;. T h i s can be mis lead ing because it takes no account o f unreactive inorganic P not determined b y the R P method or the potential over-est imation o f Pj . Therefore, a more accurate descr ip t ion o f this fraction m a y be unreactive P ( U P ) (Haygar th et al, 2000). T h e b u l k o f manures q u i c k l y become anaerobic dur ing storage 9 due to m i c r o b i a l ox ida t ion o f labi le carbon sources. Di f f icu l t i es i n chemica l ident i f icat ion o f phosphate species mean that the pathways and kinet ics o f P c y c l i n g i n manures under storage are poor ly understood. 3.2.3 Animal Manure and Environmental Impacts In general fa rm practice, manures w i l l be appl ied to the agricul tural lands as nutrients for crop growth. Excess load ing o f phosphorus to agricul tural systems causes an over-accumula t ion o f phosphorus i n the surface layer o f agricul tural soi ls . T h e transfer o f phosphorus f rom agricul tural soi ls to surface waters is a major cause o f eutrophicat ion o f both in land and coastal water bodies and cause water qual i ty problems ( F o y et al, 1995; M o s s , 1996; D a n i e l et al, 1998; Sharpley et al, 1994). These problems l i m i t water use for fisheries, recreation, industry, and d r ink ing due to the increased growth o f undesirable algae and aquatic weeds, and shortage o f oxygen . In order to address the problems caused by excessive load ing o f P to agr icul tura l systems an integrated strategy to reduce overa l l P use needs to be developed and implemented . Recove ry o f P f rom farm manures presents an opportuni ty to di rect ly contribute to such a strategy. A s m u c h as 6 5 % o f P i n an imal manures occurs i n organic forms (Barnett, 1994; Peperzak et al, 1959) w h i c h are often soluble or c o l l o i d a l i n nature and are less l i k e l y to become readi ly f ixed i n the so i l . Therefore, manure P m a y be more prone to transfer to surface waters than inorganic P f rom ar t i f ic ia l ferti l izers (Barnett, 1994; C h a r d o n et al, 1995, 1997; D a n i e l et al, 1998; Haygar th et al, 1998; Le inwebe r et al, 1997; Vet ter et al, 1980). 10 3.3 Phosphorus Recovery from Manure M a n u r e contains a large quantity o f labi le carbon and phosphorus, and i t also contains l ower concentrations o f diverse organic and inorganic contaminants. M o s t o f the phosphorus i s i n the so l id fraction. The phosphorus value o f manure depends o n the type and age o f the an ima l and the nutrients i n the an ima l feed. Domes t i c fa rm animals typ i ca l ly excrete 7 0 % o f P intake. The recovery o f phosphates offers an innovat ive n e w approach i n the treatment o f ar i imal wastes. It promises to put environmental sustainabili ty into practice. A nove l approach for deal ing w i t h materials that have considerable economic value, and w i l l be i n short supply, phosphate recovery from wastewaters is c o m i n g into vogue, par t icular ly i n Japan and Europe where environmenta l ly sustainable practices are more c o m m o n . Greaves et al. (1999) rev iewed the potential for phosphorus recovery from an imal manures as a method o f increasing the sustainabil i ty o f g lobal P cyc le . R e c o v e r y o f phosphorus f rom farm manures, i n a f o r m suitable for fert i l izer use, presents an integrated strategy to reduce the overa l l phosphorus use i n the agricul tural sector. It enables farmers to better control the appl ica t ion o f P and its release to soi ls , reduce the need to impor t further P ferti l izers and reduce the cost o f expor t ing nutrients to less susceptible or P deficient areas. Thus , the recovery o f phosphorus f rom an ima l manures w i l l be an important step i n the overa l l management and sustainabili ty o f phosphorus use. 3.3.1 Phosphorus Recovery Processes Recove ry o f P i n a fo rm suitable for fer t i l izer can reduce the need to impor t further P ferti l izers and reduce the cost o f expor t ing nutrients to less susceptible or P deficient areas. R e c o v e r y o f P from manure is l i k e l y to require t w o separate processes: (1) extract ion o f the P (to release P from the so l id fract ion into the supernatant) and (2) convers ion o f extracted P to a useful product (either c a l c i u m phosphates or magnes ium a m m o n i u m phosphate (struvite)) (Brett et al., 1997). 11 Extraction of Phosphorus Recove ry o f P w i l l require the l iberat ion o f trapped P to the aqueous phase i n a concentrated and pure enough fo rm for a process ca l led crys ta l l iza t ion to occur. P -recovery process f rom an imal manures w o u l d require pretreatment processes, to render the phosphorus i n a soluble fo rm before a c rys ta l l iza t ion process can be implemented . Conversion of Extracted Phosphorus into a Concentrated Available Form via Crystallization Phosphate i n the waste stream can be recovered by crys ta l l iza t ion techniques to y i e l d useful products such as struvite (magnes ium a m m o n i u m or potass ium a m m o n i u m phosphates) o r c a l c i u m phosphate. C a l c i u m phosphates can be recyc led into industr ial processes, or processed l o c a l l y into fert i l izers. A s the mass ratio o f Mg:NH3:PC»43" o f pure struvite is 1: 0.74: 3.2 and the mola r ratio o f Mg:NH3:PC»43" o f pure struvite is 1:1:1 (Durrant et al, 1999). Struvite has potential as an agricul tural or hort icul tural fer t i l izer because it contains P and both ni trogen and magnes ium, w h i c h plants require i n a ratio o f 3:2 M g : P (Ta i z et al, 1991). Release o f nutrients from struvite i s s low, thus m i n i m i z i n g the poss ib i l i ty to transfer P to surface waters, yet it is citrate soluble and hence avai lable to plants. The recovery o f these nutrients i n the agricultural and food wastewaters b y the crys ta l l iza t ion process w i l l be very advantageous. It contains h i g h concentrations o f potassium, ni trogen and phosphorus. T h e recovery o f phosphorus by crys ta l l iza t ion o f struvite system has been developed i n ful l-scale sewage plants i n Japan and European nations (Stratful etal, 1999). It has been reported that struvite was recovered from a variety o f an imal manures. T h e recovered struvite acts as a slow-release fer t i l izer (Schu i l i ng and Andrade , 1999; N e l s o n , 2003) . Struvite crys ta l l iza t ion and recovery have been achieved i n c a l f manure ( S c h u i l i n g and Andrade , 1999), coke manufactur ing wastewater ( Z d y b i e w s k a and K u l a , 1991), leather tanning wastewater (Tunay et al, 1997), swine wastewater (Ne l son , 2003) , and anaerobic digester sidestreams ( M o m b e r g and Oe l le rmann , 1992; M a q u e d a et al, 1994; Bat t is toni et al, 1 9 9 7 , 2 0 0 0 ; E l l i s and M i l e s , 2001 ; M u n c h and Bar r , 2001) . 12 4 M A T E R I A L S & M E T H O D S A l l experiments w h i c h were conducted i n this study were shown i n the experiment f l o w chart (see F igure 3). M a n u r e P characterization was conducted first i n this study to characterize dairy manure p H , total sol ids , ortho-P, and T P concentrations. T h e n ortho-P interference tests were carr ied out due to the d i f f icul ty to determine ortho-P concentrat ion o f dairy manure. F i n a l l y , the manure pre-treatment processes were conducted w i t h and wi thout m ic rowave treatments. 4.1 Source of Dairy Manure The P-release component o f the study was ini t ia ted b y us ing l i q u i d dai ry manure w h i c h was col lected from U B C D a i r y Educa t ion & Research Centre i n A g s s i z , B . C . The l i q u i d dai ry manure was thoroughly m i x e d and stored i n sealed 2 0 - L containers at 4 ° C un t i l needed for laboratory use. Exper iments were carr ied out dur ing a seven-month per iod f o l l o w i n g co l l ec t ion o f the waste. D e i o n i z e d water (H2O) was used to dilute the wastewater to the desired concentration. 13 Liquid Dairy Manure L j * Characterization ^ | [L Interference Tests ^ | IL Pre-treatment Process^ TS & ] pH J TP At Room T ToJ-J H A t Preset T° Nothing Added "1 Figure 3. Experiment flow chart. 14 4.2 Manure P Characterization Representative sample f rom the col lected dairy manure wastewater were analysed for p H , T S , ortho-P, and T P concentrations. Experimental Design W e l l m i x e d dairy manure and de ionized water were measured w i t h graduated cyl inders . 50 m l , 100 m l , 250 m l , and 500 m l o f l i q u i d dairy manure were measured and added into four 7 0 0 - m l beakers, and then 450 m l , 400 m l , 250 m l , and 0 m l o f de ionized water were added into four beakers respect ively, resul t ing four mixtures w i t h manure/deionized water (v/v) = 1:0, 1:1, 1:4, and 1:9 (See F igure 4). The purpose o f preparing manure di lu t ions was to study the relationship between different T S concentrations and ortho-P release capabi l i ty under mic rowave heating pretreatments. Liquid Dairy Manure { Figure 4. Dilution preparation of manure samples. F o u r samples w i t h different total so l ids concentrat ion were used for p H , T S , or tho-P, and T P analyses throughout the seven-month study per iod i n order to understand the relat ionship o f storage t ime to T S , or tho-P, and T P concentrations. Analysis The p H o f manure was measured w i t h a p H meter ( H A N N A Instrument H I 8521) and analyses, for total sol ids ( T S ) , orthophosphate (ortho-P), and total phosphate ( T P ) were carr ied out accord ing to Standard Me thods ( A P H A , 1998). A w e l l - m i x e d sample was evaporated i n a we ighed crucible and dr ied to constant weight i n an oven at 103 to 105° C. 15 T h e total P concentration was determined f o l l o w i n g K j e l d a h l digest ion. Or tho-P and T P were analyzed us ing flow inject ion analysis (Lachat Q u i k - C h e m ® 8000 Au toma ted Ion A n a l y z e r ) . T h e m i x e d l iquors were spun i n a centrifuge at 3500 r p m for 10 minutes. The resul t ing supernatants were fil tered through W h a t m a n N o . 4 filters and analyzed immedia te ly . A l l analyses were performed w i t h replicates (2 to 4) o f each different d i lu t ion . 4.3 Chemical and/or Physical Pre-treatment Process The pre-treatment process was studied b y v a r y i n g temperature condi t ions (see F igure 3). The first part o f study was carried out at r o o m temperature, and the second part was conducted at different preset temperatures w i t h m i c r o w a v e heating. 4.3.1 Room Temperature Pre-treatment Process Experimental Design F i v e sets o f experiment were conducted to evaluate P - so lub i l i za t ion i n dairy manure w i t h chemica ls addi t ion at r o o m temperature ( ~ 2 0 ° C ) . 100 m l o f l i q u i d dai ry manure was used for each set o f experiments. E a c h set o f experiment was repeated twice . Set 1, 2, and 3: These three sets were to study the ox ida t ion experiments at r o o m temperature. These experiments, w i t h different manure/H202 (v /v) ratios, were conducted at ambient temperature for a per iod up to 91 hour. Set 4: In this set, the p r imary objective was to study P release f rom manure b y add ing H2O2 and concentrated H2SO4 at ambient temperature for a per iod o f 49 hour. 16 Test Procedures Set 1: F o u r samples were prepared w i t h manure/deionized water (v/v) = 1 : 0 , 1:1, 1:4, and 1:9. H2O2 was added into dairy manure sample at ratio (v /v) o f 1:40. M i x t u r e s were stirred w i t h magnetic stirs throughout the experiment per iod i n sealed 7 0 0 - m l flasks. Set 2: T w o samples w i t h manure/deionized water (v/v) = 1:0, 1:4 were used. H2O2 / manure sample (v/v) at ratio o f 1:20. M i x t u r e s were stirred w i t h magnetic stirs throughout the experiment per iod i n sealed 7 0 0 - m l flasks. Set 3: T w o samples w i t h manure/deionized water (v/v) = 1:0, 1:4 were used. H2O2 / manure sample (v /v) at ratio o f 1:5. M i x t u r e s were stirred w i t h magnetic stirs throughout the experiment per iod i n sealed 700 -ml flasks. Set 4 : T w o samples w i t h manure/deionized water (v /v) = 1 : 0 and 1:1 were used. E v e r y 0.4 m l o f concentrated H2SO4 was added into every 20 m l o f manure first, and then every 1 m l o f H2O2 was added into every 20 m l sample. Samples were m i x e d w i t h magnet ic stirs throughout the experiment per iod i n sealed 700 -ml flasks. Sampling and Analysis S a m p l i n g o f set 1 and set 2 were carr ied out r andomly four t imes; seven samples o f set 3 were analyzed randomly; samples o f set 4 were taken randomly three t imes dur ing experimental per iod. The m i x e d l iquors were spun i n a centrifuge at 3500 r p m for 10 minutes. Supernatants were filtered through W h a t m a n N o . 4 filters, and then ana lyzed immedia te ly . Orthophosphate (ortho-P) was carr ied out accord ing to the procedures descr ibed i n Standard M e t h o d s ( A P H A , 1998), and ortho-P was ana lyzed by us ing f l o w inject ion analysis (Lachat Q u i k - C h e m ® 8000 Au toma ted Ion A n a l y z e r ) . Repl icates were performed for each run o f analyses. 17 4.3.2 Microwave Pre-treatment Process (At Preset Temperatures) Diges t ion procedures employed to release the analyte f rom an organic matr ix , to remove potent ial ly interfering organic species, or to comple te ly minera l ize the sample (e.g., for total N or P determination), are i n turn often the most lengthy stage o f the analyt ica l pro tocol . M i c r o w a v e p r inc ipa l ly is a means o f heating and pressur iz ing sample digests. T h i s area o f research had fueled the g rowth o f m ic rowave technologies because o f its superiori ty over hot plate and b l o c k digester wet a c i d digest ion methods. In search o f a rapid , efficient P - so lub i l i za t ion process, the experiments us ing m i c r o w a v e technology were therefore conducted. Pre-treatment process o f phosphorus release f rom da i ry manure was studied at var ious temperatures. F o r m ic rowave treatment, 20 m l o f manure samples, w i t h or wi thout chemica l addit ions, were heated for f ive minutes at the preset temperatures. The ramp t imes were var ied f rom 5 to 10 minutes. A p p a r a t u s A closed-vessel m i c r o w a v e digest ion system (Ethos T C Diges t ion Labsta t ion 5000, Mi l e s tone Inc.) w i t h a m a x i m u m output o f 1 0 0 0 W was used i n this study. T h i s system is equipped w i t h one sensor and up to e leven sample digest ion vessels i n a 12 pos i t ion rotating carousel . E a c h vessel w i t h 100 m l capaci ty is capable o f wi ths tanding pressure up to 30 bar (435 psig) and temperatures up to 2 2 0 ° C . The temperature is measured by a thermocouple w h i c h is located i n the sensor vessel . A mic rowave frequency o f 2450 M H z was used. The system has dual independent magnetrons w i t h a rotating mic rowave diffuser for homogeneous mic rowave dis t r ibut ion. T h e mic rowave diges t ion system: us ing an independent system control ler provides real-t ime temperature cont ro l . E x p e r i m e n t a l D e s i g n Seven sets o f experiment were conducted i n this part o f study. E a c h set o f experiment was performed three t imes repeatly. T h i s study was carr ied out w i t h one stage and t w o stages mic rowave treatment. The durat ion o f each stage treatment was f ive minutes. The first four sets, w i t h or wi thout hydrogen peroxide , was conducted at four different temperatures (60, 90 , 120 & 1 7 0 ° C ) w i t h one stage (wi th f ive minutes) m i c r o w a v e 18 treatment. The fifth set, w i t h concentrated sulfuric ac id , was carr ied out at f ive different temperatures (60, 90, 120, 150 & 1 7 0 ° C ) w i t h one stage (wi th five minutes) m i c r o w a v e treatment. The s ix th and seventh sets were to study t w o stages (wi th a total o f ten minutes) m ic rowave treatment, w i t h sulfuric ac id and hydrogen peroxide added i n reverse order, and they were conducted at four different temperatures (60, 90, 120 & 1 7 0 ° C ) . T h e p r imary objectives i n the s ix th and seventh sets were not o n l y to establish the relat ionship o f T S concentration and manure P releasing capabi l i ty i n m i c r o w a v e treatment but also to compare the o x i d i z i n g compat ib i l i ty o f sulfuric ac id and hydrogen peroxide. Tes t P r o c e d u r e s Set 1: F o u r samples w i t h manure/deionized water (v /v) = 1 :0 ,1 :1 ,1 :4 , and 1:9 were used, wi thout any chemica ls addi t ion, to process w i t h one stage m i c r o w a v e treatment. The durat ion o f m i c r o w a v e treatment was f ive minutes. There were five replicates o f each sample for each run. Set 2: T h e or ig ina l manure sample, w i t h manure/deionized water (v/v) = 1:0, was used for one stage m i c r o w a v e treatment. H y d r o g e n peroxide was added w i t h manure/H202 (v/v) ratio o f 20:1 (1 m l o f H2O2 for every 20 m l o f manure). T h e durat ion o f m i c r o w a v e treatment was f ive minutes. There were f ive replicates o f each sample for each run. Set 3: T h e o r ig ina l manure sample, w i t h manure/deionized water (v/v) = 1:0 was used for one stage mic rowave treatment. H y d r o g e n peroxide was added at the dairy manure/H202 (v/v) ratio o f = 10:1. T h e durat ion o f m i c r o w a v e treatment was f ive minutes. There were f ive replicates o f each sample for each run. Set 4: T h e or ig ina l manure sample, w i t h manure/deionized water (v /v) = 1:0 was used, w i t h hydrogen peroxide added at the ratio o f dairy manure /hbG^ (v/v) = 5:1 (1 m l o f H2O2 for every 5 m l o f manure). T h e durat ion o f mic rowave treatment was f ive minutes. There were f ive replicates o f each sample for each run. 19 Set 5: Three samples with manure/deionized water (v/v) = 1:0, 1:4, and 1:9 were used, with concentrated sulfuric acid. 0.4 ml of H2SO4 for every 20 ml of manure sample, and mixed liquors were undertaken five minutes microwave treatment. Five replicates of each sample were performed in each run. Set 6 and 7: Two stages of microwave treatment were conducted in set 6 and 7. Three samples with different total solids (TS) concentrations were prepared for these two sets of experiment: sample 1 (TS = 1.57%): measuring mixed well manure by graduate, sample 2 (TS = 1.36%): pipette was used to measure mixed well manure, and sample 3 (TS = 0.93%): Supernatants of manure. The mixed manure was spun in a centrifuge at 3500 rpm for 10 minutes, and then supernatant was collected as sample 3. Same quantity of chemicals - 1 ml of H2O2 and 0.4 ml of concentrated H2SO4 - were added into 20 ml of manure in set 6 & 7. In set 6, first Stage: H2SO4 was added first into manure and the mixed liquors were treated with five minutes microwave treatment at preset temperature. After the first stage treatment, liquors were cooled down to room temperature, and then concentrated H2SO4 was added for the second stage of microwave treatment - for another five minutes. Chemicals were added in reverse order in set 7: H2O2 added for the first stage microwave treatment, and then H2SO4 added for the second stage microwave treatment. The duration of each stage microwave treatment was five minutes; samples were treated for a total of ten minutes. Four replicates of sample 1 & 2 &3 were performed for each run at preset temperatures. Sampling and Analysis Sampling was carried out immediately after the microwave treatment. The mixed liquors were spun in a centrifuge at 3500 rpm for 10 minutes. The resulting supernatants were filtered through Whatman No.4 filters and analyzed immediately. Ortho-P was carried out according to the procedures described in Standard Methods (APHA, 1998) and analyzed using flow injection analysis (Lachat Quik-Chem® 8000 Automated Ion Analyzer). Replicates were performed for each run of analyses. 20 5 R E S U L T S & D I S C U S S I O N S The results presented here include dai ry manure characterization, manure pretreatment processes at var ious temperatures w i t h and without chemicals addi t ion. The tables o f results were arranged i n the appendix. 5.1 Dairy Manure P Characterization 5.1.1 pH The p H o f four dai ry manure mixtures w i t h manure/deionized water (v/v) = 1:0, 1:1,1:4, and 1:9 were moni tored once every month throughout the seven-month study per iod. The results are as s h o w n i n F igure 5 and Table A - l . T h e p H o f four samples fluctuated s l ight ly dirr ing the seven-month study per iod (June 2004 ~ December 2004), indicat ing that the p H o f dairy manure was neutral, and var ied f rom 7.6 to 8.2 dur ing a seven-month per iod. 9.00 8.60 8.20 X C L 7.80 7.40 7.00 Apr-2004 Jun-2004 Aug-2004 Sep-2004 Sampling Month Nov-2004 Dec-2004 •Dairy manure/Deionzied water (v/v)=1:0 Dairy manure/Deionized water (v/v)=1:4 Dairy manure/Deionized water (v/v)=1:1 •Dairy manure/Deionized water (v/v)=1:9 Figure 5. Relationships of pH of manure/deionized water (v/v) to stored time in dairy manure. 21 5.1.2 Total Solids In June 2004, four dairy manure mixtures with manure/deionized water (v/v) = 1:0, 1:1, 1:4, and 1:9 had four different total solids concentrations: 1.28%, 0.62%, 0.25%, and 0.11% respectively. In December 2004, total solids concentration of four samples with the same dilution ratios increased to 1.60%, 0.78%, 0.31%, and 0.15%, respectively (See Figure 6 and Table A-lof Appendix A). The differences of TS concentration of these four samples were 0.32%, 0.16%, 0.06%, and 0.04%, respectively after the seven-month study period. The increase of TS concentration might possibly be caused by sampling errors due to the heterogeneity of stored dairy manure and the difficulty for sampling thoroughly homogeneous manure sample from the storage container. 2004 0.00 Apr-2004 Jun-2004 Aug-2004 Sep-2004 Sampling Month Nov-2004 Dec-2004 • Dairy manure/Deionized water (v/v)=1:0 - » - Dairy manure/Deionized water (v/v)=1:1 Dairy manure/Deionized water (v/v)=1:4 - • - Dairy manure/Deionized water (v/v)=1:9 Figure 6. Relationships of TS concentration of manure/deionized water (v/v) to stored time in dairy manure. 22 5.1.3 TP Concentration Results as shown in Figure 7 indicated that TP concentration of dairy manure increased from 117.5 ± 12.2 mg/L to 227.2 ± 9.1 mg/L from June 2004 to December 2004 (in Table A-2 of Appendix A). Three explanations for the increase of TP concentration may be a) the dairy manure was stored under nearly anaerobic condition during the seven-month study period; therefore, more phosphate was released and became more available in the manure as storage time increased, b) the dairy manure was not totally digested by following the Kjeldahl digestion method; therefore, total phosphate can not be released totally, and c) sampling errors. 250 O CL I— 50 0 -I 1 1 1 1 1 Apr-2004 Jun-2004 Aug-2004 Sep-2004 Nov-2004 Dec-2004 Sampling Month Figure 7. Relationship of TP concentration to stored time in dairy manure. 23 5.1.4 Ortho-P Concentration Four samples w i t h manure/deionized water (v/v) = 1:0, 1:1, 1:4, and 1:9 were used for ortho-P analysis . Resul ts were summar ized i n Tab le A - 3 o f A p p e n d i x A . In F igure 8, it was observed that an increasing d i lu t ion ratio (1 /1-1/9) resulted i n an increased measured ortho-P concentrat ion up to 4 t imes. Apparen t ly , the increased d i lu t ion caused the greater magnif ica t ion o f the interferences from u n k n o w n compounds i n the dairy manure. Or tho-P concentration decreased as manure v o l u m e increased, indicat ing a posi t ive effect o f d i lu t ion by de ionized water o n manure ortho-P concentration. K l e i n m a n et al. (2002) also reported the existence o f posi t ive effects o f d i lu t ion by de ionized water o n manure ortho-P concentration, and their explanat ion was that d i lu t ion o f manure promoted the d issolu t ion o f insoluble c a l c i u m phosphates and, therefore, higher water-extractable phosphorus ( W E P ) concentrations. 140 T - — 0 "I 1 1 1 1 1— — i 1 1 1— — i 1 0 1/10 2/10 3/10 4/10 5/10 6/10 7/10 8/10 9/10 1 1 1/10 Manure/ Deionized water (v/v) Figure 8. Relationship of manure/deionized water (v/v) and ortho-P concentrations in dairy manure (mean of ten observations). 24 T o f ind out what factors caused posi t ive interference o n ortho-P concentrat ion was important and interference e l imina t ion should be conducted pr ior to dai ry manure phosphate release pre-treatment process. 5.1.4.1 Verification of Ortho-P Interference In addi t ion to be ing used to analyze the sample, the proposed procedure is tested against port ions o f the sample to w h i c h k n o w n amounts o f the analyte have been added. T h e effectiveness o f the method can then be established b y evaluat ing the extent o f recovery o f the added quantity. T h e standard-addition method m a y reveal errors ar is ing f rom the w a y the sample was treated o r f rom the presence o f the other elements and/or compounds i n the matr ix . Here , three k n o w n amount o f the analyte - 100 , 50 and 25 m g P / L - were added into three sets o f samples (manure/deionized water (v/v) = 1:0, 1:1, 1:4, and 1:9) w i t h the v o l u m e ratio o f 1:1, and then the extent o f recovery o f the added quantity was evaluated. In F igure 9, every set o f experiment had two same co lor l ines to show results - the s o l i d l ine showed the result o f the extent o f recovery o f the added quantity (as summar ized i n Table B - l o f A p p e n d i x B ) , and the dotted l ine resulted f rom the idea l ly 100% recovery o f the added quantity (as summar ized i n Table B - 2 o f A p p e n d i x B ) . B y compar ing the s o l i d and dotted l ines, it can be seen that the difference o f ortho-P concentrat ion increased as by manure v o l u m e decreased, demonstrat ing a posi t ive interference caused b y d i l u t i on o f de ion ized water o n manure ortho-P concentrat ion (as summar ized i n Table B - 2 o f A p p e n d i x B ) . Interference was evident. 25 EL OS E c o as o c o O CL i O JZ •c O 120 100 80 60 40 20 0 0 • * " ' A . . • • * ~ — — ^ * ^ % % % % A . . . . Im, •-" A * * - . m m m A • m —\ " - • 1/10 2/10 3/10 4/10 5/10 6/10 7/10 8/10 Manure/Deionized water (v/v) 9/10 1 1 1/10 •Set 1 : Spike with 25 mg P/L - *• Expected Con. Of Set 1 • Set 2 : Spike with 50 mg P/L A Expected Con. Of Set 2 •Set 3 : Spike with 100 mg P/L - • - Expected Con. Of Set 3 Figure 9. Relationship of manure/deionized water (v/v) to ortho-P concentrations in dairy manure with standard addition. 5.1.4.2 Automated Ascorbic Reduction Method Principle Ammonium molybdate and potassium antimonyl tartrate react with orthophosphate ion (PO43") in an acid medium to form an antimony-phosphomolybdate complex, which, on reduction with ascorbic acid, yields an intense blue color suitable for photometric measurement. The blue complex absorbs light at 880 nm, and the absorbance is proportional to the concentration o f orthophosphate in the sample. The molybdenum blue methods are the most sensitive and as a result are widely used. The intensity of the blue color varies with the P concentration but is affected also by other factors such as acidity, arsenates, silicates, and substances which influence the oxidation-reduction conditions of the system. 26 Interferences Turb id i ty , arsenate (AsC»43~), s i l i ca , s i l i c o n d iox ide (S iCh) , copper ( C u ) , ferric i r on ( F e 3 + ) , salt, N O 2 * , and S 2", w i l l interfere i n the format ion o f m o l y b d e n u m blue co lo r w i t h P ( A P H A , 1998). Sample co lo r that absorbs i n the photometric range used for analysis also w i l l interfere. A s m u c h as 50 m g F e 3 + / L , 10 m g C u / L , 10 m g Si02/L, and 0.1 m g A S O 4 3 " / L can be tolerated. Fer r ic i r on causes a negative error due to compet i t ion w i t h the complex for the reducing agent ascorbic ac id . S i l i c a forms a pale b lue c o m p l e x that also absorbs at 880 n m ; therefore, h i g h s i l i c a concentrations cause posi t ive interference. Arsenate (ASO43") i s a posi t ive interference, because arsenates i n concentrations as l o w as 0.1 m g A s / L react w i t h molybdate reagent to produce a s imi la r b lue color . Sal t concentrations up to 2 0 % (w/v) cause an error o f less than 1%. E l i m i n a t i o n o f the interference f rom N O 2 " and S 2 " m a y be accompl i shed b y adding an excess o f b romine water or a saturated potass ium permanganate (KMn04) solut ion. 5.1.5 Tests of Interference Elimination T h e increased d i lu t ion caused the greater magni f ica t ion o f the interferences f rom u n k n o w n compounds i n the dairy manure. Because sample color , turbidi ty, and some metals c o u l d cause interference o f the format ion o f m o l y b d e n u m blue w i t h P , some tests for e l imina t ing the interference such as f i l t rat ion, decolonizat ion, and extract ion were conducted. 5.1.5.1 Filtration & Decolorization It was necessary to remove interfering turbidi ty by f i l t rat ion before analysis . A c t i v a t e d charcoal was used for decolor iza t ion o f sample color . Samples , w i t h and wi thout decolor iza t ion , were ana lyzed b y U V - V I S spectrophotometer w h i c h was set at 880 n m . The results o f spectrophotometer were w i t h n o n absorbance at wavelength o f 880 n m , indica t ing that sample co lo r was not the factor to cause interference o f ortho-P 27 concentration. Therefore, decolor iza t ion is not necessary i f co lo r development is by the molybdophosphor ic blue co lor procedure (Jackson, 1958). T w o set o f samples were treated w i t h the same amount o f activated charcoal and received different length o f react ion t ime exposure - f ive minutes and eight hours. The results as shown i n F igure 10 indicate that ortho-P concentration decreased as reaction t ime increased. One possible explanat ion m a y be that activated charcoal absorped ortho-P and the degree o f absorption increased w h e n reaction t ime was longer; therefore, it caused negative interference w i t h ortho-P concentration. Resul ts were summar ized i n Table C - l o f A p p e n d i x C . 120 Manure/Deionized water (v/v) - • - N o t h i n g Added - " -Ac t i va ted Charcoal Added (For 5 minutes) - • -Ac t i va ted Charcoal Added (For 8 hours) Figure 10. Relationship of manure/deionized water (v/v) to ortho-P concentration in dairy manure with decolorization. 28 5.1.5.2 Extractions Hydrochloric acid & Sodium bicarbonate Phosphorus is extracted with 0.5 M sodium bicarbonate (NaHCOa) at a nearly constant pH of 8.5. As the pH rises, a fraction of the bicarbonate (HCO3) changes to carbonate (CO3). The C O 3 2 ' ions precipitate calcium (Ca) from labile calcium phosphates, thus dissolving labile phosphorus (P). This extractant decreases the concentration of Ca in solution by causing precipitation of Ca as CaCC»3; as a result, the concentration of P in solution increases. Iron phosphate dissolves in concentrated hydrochloric acid solution, resulting in higher ortho-P concentration. The results as shown in Figure 11 indicate that sodium bicarbonate and hydrochloric acid are able to dissolve labile phosphorus, resulting in higher ortho-P concentrations. Therefore, we could possible assume that either calcium phosphates or iron phosphates were the factor to induce the interference on ortho-P concentration. Results were summarized in Table C-2 of Appendix C. 200 -T - - 1 1 1/10 Manure/Deionized water (v/v) ^Nothing Added - • - HCI Added NaHCQ3 Added Figure 11. Relationships of manure/deionized water (v/v) with ortho-P concentrations in dairy manure with extractant of HCI/NaHC0 3. 29 Sodium bisulfite Arsenate (AsC»43~) is a pos i t ive interference, because arsenates i n concentrations as l o w as 0.1 m g A s / L react w i t h molybdate reagent to produce a s imi l a r b lue color . Interference b y arsenate can be avo ided by reducing AsC»43" to AsC»33" w i t h N a H S 0 3 (Jackson, 1958). S o d i u m bisulfi te (NaHSC»3) reduces arsenic ac id to arsenious ac id and ferric i ron to ferrous form. These reduced forms o f arsenic and i ron do not interfere. Resul ts were summar ized i n Tab le C-3 o f A p p e n d i x C. Resul ts i n F igure 12 showed that ortho-P concentrations increased by us ing NaHS0 3 , indica t ing the interference o f ortho-P concentrat ion i n this study was not caused by arsenate and i ron . 180 T— 160 0 -I 1 1 1 1 1 1 1 1 1 1 1 0 1/10 2/10 3/10 4/10 5/10 6/10 7/10 8/10 9/10 1 1 1/10 Manure/Deionized water (v/v) ! -»- Nothing - • - NaHSQ3 Added Figure 12. Relationship of manure/deionized water (v/v) to ortho-P concentrations in dairy manure with extractant of NaHSC>3. Ammonium fluoride & Hydrochloric acid The extracting reagent - the combina t ion o f hydroch lo r ic a c i d (IN, HC1) and a m m o n i u m fluoride (IN, NH4F) - i s designed to remove easi ly acid-soluble forms o f P , largely c a l c i u m phosphates, and a por t ion o f the a l u m i n u m and i r on phosphates. The NH4F dissolves a l u m i n u m and i ron phosphates by its c o m p l e x i o n format ion w i t h these metal 30 ions i n ac id condi t ion . T h e results as shown i n Figure 13 showed that on ly ortho-P concentration o f or ig ina l manure sample - sample w i t h manure/deionized water (v/v) = 1:0 - decreased; resul t ing i n a negative interference o n ortho-P concentration i n the or ig ina l manure sample. Therefore, the posi t ive effect o f d i lu t ion by de ion ized water o n manure ortho-P concentrat ion was not e l iminated by us ing the extracting reagent. Resul ts were summar ized i n Table C - 3 o f A p p e n d i x C . 160 1 1/10 Manure/Deionized water (v/v) | - • - Nothing Added - • - Extracting Reagent Added Figure 13. Relationship of manure/deionized water (v/v) to ortho-P concentrations in dairy manure with extracting reagent - HCI + NH 4F. Hydrogen peroxide H y d r o g e n peroxide (H2O2) is a powerfu l versatile oxidant that is both safe and effective. H2O2 is one o f the most powerfu l ox id ize r s k n o w n — stronger than chlor ine , ch lor ine d iox ide , and potass ium permanganate. H2O2 can treat both easy-to-oxidize pollutants ( i ron and sulfides) and di f f icu l t - to-oxid ize pollutants (solvents, gasolines and pesticides). H2O2 can o x i d i z e ferrous i o n , manganese, arsenic, and se lenium to improve their adsorption, f i l t rat ion, or precipi ta t ion from wastewater. 31 The ratio o f manure/H202 = 40:1 was used i n two studies - 1) w e l l m i x e d manure samples w i t h manure/deionized water (v/v) = 1:0, 1:1, l :4 ,and 1:9, and 2) supernatant on ly o f manure w i t h manure/deionized water (v/v) = 1:0, 1:1, l :4 ,and 1:9. The results as shown i n F igure 14 showed that H2O2 induced the decrease o f ortho-P concentration as manure v o l u m e increased, and there was not m u c h change o n ortho-P concentration o f manure samples w i t h manure/deionized water (v/v) = 1:4 and 1:9. Results were summar ized i n Tab le C - 4 o f A p p e n d i x C . H y d r o g e n peroxide couldn ' t e l iminate the posi t ive effects o f d i lu t ion by de ionized water on manure ortho-P concentration. 0 A 1 , , , 1 , , , , , 1 0 1/10 2/10 3/10 4/10 5/10 6/10 7/10 8/10 9/10 1 1 1/10 Manure/Deionized water (v/v) - • - Original Sample H202 Added into Supernatant Sample i -•-H202 Added into Original Sample j Figure 14. Relationships of manure/deionized water (v/v) to ortho-P concentrations in dairy manure with H2O2. Summary of Interference Elimination Tests Turb id i ty , sample color , arsenate ( A S O 4 "), s i l i ca , s i l i con d iox ide (S iG^) , copper (Cu) , ferric i ron (Fe ), salt, N O \ and S ~, a l l w i l l interfere i n the formation o f m o l y b d e n u m blue co lor w i t h P . The greater d i lu t ion o f manure magnif ied the posi t ive effect o n measured ortho-P concentration; therefore, several interference e l imina t ion tests were 32 conducted. T h e intension for running these tests was to f ind out what factors were those caused the interference and h o w to el iminate it. The results o f tests conf i rmed that turbidi ty and sample co lo r were not factors to cause interference for ortho-P determination. Several different extracting reagents w h i c h were w i d e l y used i n s o i l science were also used i n these tests. A c c o r d i n g to the test results, a l l extractants and hydrogen peroxide fa i led to el iminate the interference. A dai ry c o w is a ruminant , and has four stomachs: rumen, re t icu lum, omasum, and abomasum. Di f f icu l t i es i n e l imina t ing interference o f ortho-P concentrat ion mean that the enzymes, composites , pathways and kinet ics o f P c y c l i n g i n manures are poor ly understood. H o w e v e r , the interference was not able to be e l iminated i n this study; the extent o f magni f ica t ion o f the interferences f rom the u n k n o w n compounds i n the dairy manure was k n o w n . Therefore, the or ig ina l manure sample (manure/deionized water (v/v) = 1:0) w h i c h was col lec ted direct ly f rom the farm was chosen as the m a i n study mater ial to pursue the research o f manure pre-treatment process. 5.2 Manure Pre-treatment Process D i s s o l v e d phosphate is frequently determined i n studies o f the aquatic environment and i n waste management. Phosphate is a nutrient con t ro l l ing a lga l growth, par t icular ly i n enclosed or poor ly f lushed water bodies such as lakes or r ivers . Excess ive levels can lead to excessive a lgal growth . In addi t ion to orthophosphate, natural ly occur r ing and anthropogenic phosphate can occur i n a number o f different forms, both as po lymer i c inorganic species and as organophosphate species. The most c o m m o n means o f determining phosphate is by the co lor imet ry based o n phosphomolybdenum blue chemistry method but a core aspect o f the method is that on ly the orthophosphate i o n is measured. A l l other forms o f phosphorus ( inorganic polyphosphate and organic phosphorus compounds , for example) have first to be converted into orthophosphate b y a digestive or oxida t ive procedure. 33 The color imet r ic determination o f phosphate can i nvo lve a complex sequence o f steps result ing from the need to convert naturally occur r ing compounds into orthophosphate. T h e b reakdown o f organophosphate compounds to inorganic phosphate has been carr ied out i n a number o f different ways . C h e m i c a l ox ida t ion o f the organics can be carr ied out i n batchs, us ing reagents such as hydrogen peroxide and sulfuric ac id and by treatment w i t h mic rowaves ( K i n g s t o n et al, 1988). S u c h methods have been adapted for use i n continuous f l o w analyzers us ing m i c r o w a v e (Benson et al, 1994) o r more convent ional heating methods ( E b i n a et al, 1983). In order to recover phosphorus from manure v i a crys ta l l iza t ion , it is necessary to undertake a P - so lub i l i za t ion process to release phosphate into the solut ion. M a n y P -so lub i l i za t ion processes require either addi t ion o f chemicals to initiate reactions, or need a l ong per iod o f t ime to complete the reaction. In search o f a rapid , efficient P -so lub i l i za t ion process, m ic rowave digest ion techniques were used. The pre-treatment process o f phosphorus release from dairy manure was studied at var ious temperatures. The first part o f the study was carr ied out at r o o m temperature, and the second part was conducted at different preset temperatures w i t h m ic rowave treatment. 5.2.1 Room Temperature Pre-treatment Process Hydrogen peroxide Hydrogen peroxide is an excellent oxidant reagent. T y p i c a l l y concentrations o f about 3 0 % hydrogen peroxide are used i n digestions. T h e results as shown i n F igu re 15 showed that an addi t ion o f H2O2 into or ig ina l manure sample at ambient temperature (1/20 ratio), released 34.9 m g / L o f phosphate after 5 hours o f react ion t ime; after 8 hours o f react ion t ime, ortho-P concentrat ion dropped 10.7 m g / L , afterwards, and then phosphate release remained constantly for a per iod o f 76 hours. Resul ts showed that 15 .5% o f T P i n manure was released after an eighty-four-hour study per iod . T h i s represents a phosphate recovery rate o f 32 .6% (refer to Tab le D - l o f A p p e n d i x D ) . The results indicated that the amount 34 o f H2O2 w h i c h was added for the ox ida t ion process was insufficient to release the ideal amount o f phosphate f rom manure. Therefore, the amount o f H2O2 was increased. The results i n F igure 15 show that 93.7 m g / L o f phosphate was released after 80 hours reaction t ime w i t h an addi t ion o f H2O2 into manure sample at ambient temperature (1/5 ratio). T h i s showed that 6 6 . 5 % o f T P i n manure was released and 8 3 . 1 % o f phosphate was recovered ( in Table D - 2 o f A p p e n d i x D ) . The results proved that an oxida t ion process c o u l d be a means o f so lub i l i za t ion o f phosphorus from manure by adding sufficient amount o f H2O2. The ox ida t ion process foamed rapidly ; therefore, large v o l u m e containers were needed for accommodat ing mass ive foams caused b y oxida t ion . Despi te good results by adding large quantity o f H2O2 into manure, i t ' s not economica l and pract ical . 0 -I 1 1 1 1 1 1 1 ! 0 10 20 30 40 50 60 70 80 90 Reaction Time (Hour) !-*-H2Q2/Manure = 1:20 - • - H2Q2/Manure = 1:51 Figure 15. Relationship of reaction time to ortho-P concentrations in dairy manure with H2O2 oxidation (mean of four observations). 35 Combined sulfuric acid and hydrogen peroxide H y d r o g e n peroxide is usual ly combined w i t h an ac id because its o x i d i z i n g power increases as the acidi ty increases. Concentrated sulfuric ac id is a powerful dehydrating agent. It forms hydrates H2SO4T1H2O. In dilute aqueous solut ion, sulfuric ac id is a n o n o x i d i z i n g ac id . H o w e v e r , when concentrated and hot, it is an o x i d i z i n g agent. The combina t ion o f hydrogen peroxide and sulfuric ac id forms monoperoxosulphur ic ac id (H2SO5), w h i c h is a very strong o x i d i z i n g reagent ( B o c k , 1979). Because o f its o x i d i z i n g power , hydrogen peroxide is frequently added after comple t ing the pr imary acidi f ica t ion i n the pre-digestion o f the matr ix . The hydrogen peroxide can complete the digest ion and the potential safety hazards are m i n i m i z e d . 220 O 180 170 "i . 1 1 0 10 20 30 40 50 60 Reaction Time (Hour) Figure 16. Relationship of reaction time to ortho-P concentrations in dairy manure with combined H2SO4/H2O2 (mean of four observations). The experiments w i t h addi t ion o f combined H2SO4/H2O2 were conducted at r o o m temperature w i t h 100 m l o f o r ig ina l manure sample i n 2 - L containers. Dupl icates were performed for each set o f experiment, and each set o f experiment was rerun two t imes. It 36 foamed mass ively , and the foam settled d o w n very s l o w l y ; therefore, a b i g container was needed to accommodate massive amount o f foams. The trend o f phosphate release increased steadily. The results as presented i n F igure 16 showed that 166.0 m g / L o f phosphate was released immedia te ly after comple t ion o f chemica ls addi t ion. Af ter 49 hours o f reaction t ime, ortho-P concentration increased 184.0 m g / L . It showed that 81 .0% o f T P i n dairy manure was released, indica t ing that phosphate recovery rate was 93 .2%. Results were summar ized i n Table D - 3 o f A p p e n d i x D . The results indicated that phosphate cou ld be released opt imis t ica l ly w i t h combined H2SO4/H2O2 addi t ion. 5.2.2 Microwave Pre-treatment Process One Stage Microwave treatment only (without chemicals addition) 120 0 A . . , 1 : 1 0 30 60 90 120 150 180 Temperature ( ° C ) -•-Sample 1: Manure/DI water (v/v) = 1:0 -"-Sample 2: Manure/DI water (v/v) = 1:1 Sample 3: Manure/DI water (v/v) = 1:4 - • - Sample 4: Manure/DI water (v/v) = 1:9 Figure 17. Relationship of temperature on ortho-P concentrations in dairy manure with microwave treatment only (mean of fifteen observations). 37 The purpose o f this experiment was not on ly to determine the effect o f temperature o n phosphate release but also to compare the trends o f phosphate release for four samples w i t h manure/deionized water (v/v) = 1:0, 1:1, 1:4, and 1:9. Therefore, four operating temperatures were used o n each sample. The results are presented i n F igure 17. The trends o f sample 1 & 2 were s imi lar . The trend o f sample 3 was s imi la r to the trend o f sample 4. Phosphate release for sample 1 & 2 reached the m i n i m u m at 9 0 ° C , and the highest phosphate release was a lso obtained at 1 7 0 ° C . F o r sample 3 & 4, at 1 7 0 ° C phosphate release reached the m i n i m u m , and at 6 0 ° C the highest phosphate release was obtained. D u e to the diff icul t ies i n e l imina t ing interference o f ortho-P concentration, an or ig ina l manure sample (sample 1: manure/deionized water (v /v) = 1:0) was chosen to be the m a i n study material for pursuing the research o n manure pre-treatment process; therefore, on ly data o f sample 1 was adopted for the study. In F igure 17, the results obtained f rom the m a i n study material - o r ig ina l manure sample - sample 1 showed that a decrease o f phosphate release as an increase o f temperature from 6 0 ° C to 9 0 ° C . One possible explanat ion may be that the result ing solu t ion contained most o f polyphosphate instead o f soluble phosphate at 9 0 ° C . S i m i l a r results o f activated sludge were also obtained b y K u r o d a et al. (2002). The results were summar ized i n the Table E - l o f A p p e n d i x E . The results were represented i n F igure 17. F o r sample 1, the highest phosphate release was also obtained at 1 7 0 ° C . 15.8 m g / L o f phosphate was released at 1 7 0 ° C , and it was represented that 13.4% o f T P i n manure was released. Therefore, the phosphate recovery rates were 3 5 . 0 % for mic rowave treatment. The results indicated that m ic rowave treatment alone d idn ' t w o r k as w e l l as expected o n phosphate release f rom dairy manure. It was clear that phosphate release was h i g h l y depending o n temperatures appl ied i n the process under m ic rowave treatment. 38 Combined EhOz/one stage microwave Treatment A d v a n c e d ox ida t ion processes ( A O P ' s ) represent the newest development i n H2O2 technology, and are loosely defined as processes that generate h i g h l y reactive oxygen radicals without the addi t ion o f metal catalysts. T y p i c a l l y , this means c o m b i n i n g H2C»2 w i t h ozone or ultraviolet l ight . The result is the on-site total destruction o f even refractory organics wi thout the generation o f sludges or residues. T h i s technology is being w i d e l y appl ied to treat contaminated groundwaters, to purify and disinfect d r ink ing waters and process waters, and to destroy trace organics i n industrial effluents (Sapach and viraraghavan, 1997). Sana et al. (2002) reported that phenol c o u l d be o x i d i z e d completed i n A O P ' s us ing H.202/microwave irradiat ion, and the mic rowave process was superior to the convent ional Fenton ox ida t ion technique. 60 - r - - , j 50 o 10 0 \ 1 1 1 • 0 30 60 90 120 150 180 Temperature (°C) -*-SET1:Manure/H202 (v/v)=20:1 -"-SET2:Manure/H202 (v/v)=10:1 j-*-SET3:Manure/H2Q2 (v/v)=5:1 Figure 18. Relationship of temperature on ortho-P concentrations in dairy manure with AOP's (mean of fifteen observations). Phosphorus was not released into solu t ion under the mic rowave treatment only . It was hypothesized that by us ing the combined F L ^ / m i c r o w a v e process, this cou ld have a 39 synergist ic effect o n the release o f phosphorus into solu t ion f rom dairy manure. A n or ig ina l manure sample (manure/deionized water (v/v) = 1:0) was used to be the study material i n A O P ' s . The results o f the ox ida t ion experiments were summar ized i n the Table E - 2 o f A p p e n d i x E . Phosphate release, w i t h different manure / JbG^ ratios, gave s imi la r trends as showed i n Figure 18. The m a x i m u m so lub i l i za t ion o f phosphate was obtained at 6 0 ° C ; the lowest phosphate concentration was at 120°C . M o r e phosphate was released w h e n larger amount o f H2O2 were added. The results i n F igure 18 showed that a decrease o f phosphate release w h e n temperature was greater than 6 0 ° C . One possible explanat ion may be that the l o w soluble phosphate i n the solu t ion was due to the presence o f intermediate products o f polyphosphates at higher temperature. The results i n F igure 18 showed that i n S E T 1, w i t h manure/H202 = 20 :1 , 15.8 m g / L o f phosphate was released at 6 0 ° C , and this indicated that 13.4% o f T P i n manure was released, w h i l e o n l y 8.3 m g / L o f phosphate was release at 170°C . S E T 2 w i t h manure/H202 = 10:1, 23.0 m g / L o f phosphate was released at 6 0 ° C . T h i s represented a release o f 19.6% o f T P i n manure, w h i l e on ly 16.5 m g / L o f phosphate was release at 170°C. S E T 3 w i t h m a n u r e / H 2 0 2 = 5:1, 30.3 m g / L o f phosphate was released at 6 0 ° C . T h i s represented a release o f 25 .8% o f T P i n manure, w h i l e on ly 20.5 m g / L o f phosphate was release at 1 7 0 ° C . Therefore, for combined H202/microwave treatment at 6 0 ° C , the phosphate recovery rates o f S E T 1, S E T 2, and S E T 3 were 28 .0%, 3 4 . 1 % , and 4 0 . 3 % respectively. The results indicated that A O P ' s were not capable to enhance phosphorus release f rom dairy manure even at h igh temperatures. Combined H?SOd/one stage microwave Treatment Concentrated sulfuric ac id (98.7%) w i t h a b o i l i n g point o f 3 3 9 ° C was used i n the combined ^ S O V m i c r o w a v e process. Concentrated sulfuric ac id is a powerfu l dehydrat ing agent. It forms hydrates H2SO411H2O. D i l u t e sulfuric ac id does not exhibi t any o x i d i z i n g properties, but the concentrated ac id is capable o f o x i d i z i n g many substances ( B o c k , 1979). The ratio o f F b S O v r n a n u r e was 1:50. 40 The phosphate release trends o f three samples w i t h manure/deionized water (v/v) = 1:0, 1:4, and 1:9 were s imi la r as showed i n F igure 19. T h e results o f three samples showed that a decrease o f phosphate release occurred as temperature was increased f rom 6 0 ° C to 9 0 ° C . One possible explanat ion o f the lower phosphate concentration at 9 0 ° C may be that at 9 0 ° C the result ing so lu t ion contained mos t ly polyphosphate, instead o f soluble phosphate. The m a x i m u m so lub i l i za t ion o f phosphate was obtained at 1 7 0 ° C ; the lowest phosphate concentration was at 9 0 ° C . Phosphate release f rom dairy manure w i t h H2SO4 addi t ion was h i g h l y temperature dependent i n the mic rowave treatments. The results were summar ized i n the Table E - 3 o f A p p e n d i x E . 0 -I 1 1 1 1 1 1 0 30 60 90 120 150 180 Temperature (°C) -•-Sample 1: Manure/water (v/v) = 1:0 -"-Sample 2: Manure/water (v/v) = 1:4 Sample 3: Manure/water (v/v) =1:9 Figure 19. Relationship of temperature to ortho-P concentrations in dairy manure with H2S04/microwave process (mean of fifteen observations). The results i n Figure 19 showed that three samples w i t h different manure/deionized water ratio c o u l d reach the same ortho-P concentrat ion at 170°C , and the possible explanat ion might be that interference o n ortho-P measurement might be e l iminated by app ly ing the 41 combined H i S O V m i c r o w a v e process. D u e to the uncertainty o f ortho-P concentrat ion interference e l imina t ion by us ing combined ^ S O V m i c r o w a v e process, on ly the results o f o r ig ina l manure sample (sample 1: manure/deionized water (v /v) = 1:0) were used for the combined ^ S O V m i c r o w a v e treatment. A s s h o w n i n F igure 19, the highest phosphate release o f sample 1 was obtained at 1 7 0 ° C . 148.4 m g / L o f phosphate was released at 1 7 0 ° C , and it was represented that 82 .2% o f T P i n manure was released. Therefore, the phosphate recovery rates were 91 .4% for the combined F b S C V m i c r o w a v e treatment. T h e results indicated that phosphorus was released eff iciently into solu t ion under the combined H a S C V m i c r o w a v e treatment. C o m b i n e d H ^ S O j / H ^ O g / t w o stages m i c r o w a v e T r e a t m e n t Sulfur ic ac id is c o m m o n l y used w i t h other acids and reagents. One o f the most c o m m o n combinat ions is w i t h hydrogen peroxide. Sul fur ic ac id w i l l act as a dehydrat ing agent that w i l l dramat ical ly increase the o x i d i z i n g power o f hydrogen peroxide, but the mixture m a y react too v io len t ly w i t h organic matrices i n c losed vessels or i f heated rapid ly . Because o f its o x i d i z i n g power , hydrogen peroxide i s frequently added after the p r imary ac id has completed a pre-digest ion o f the matr ix . The hydrogen peroxide can complete the digest ion and the potential safety hazards are m i n i m i z e d . T w o sets o f two stages mic rowave treatment experiment were conducted not on ly to compare any difference w h i c h was induced b y the opposite chemicals addi t ion sequence but also to verify whether most o f the phosphate was i n so l id fo rm i n dairy manure. Three samples w i t h different T S concentration were used i n the experiments. A n or ig ina l manure sample (manure/deionized water (v/v) = 1:0) was used to prepare for sample 1, 2, & 3 . Sample 1 had T S = 1.57%. Sample 2 had T S = 1.36%. Sample 3 had T S = 0 .93%. In set 1, hydrogen peroxide was added after a pre-digest ion o f the matr ix w i t h p r imary sulfuric ac id , and w i t h f ive minutes m ic rowave treatment. H y d r o g e n peroxide had completed digest ion w i t h the second stage (5 minutes) m ic rowave treatment. In set 2, hydrogen peroxide was added before sulfuric a c i d was added. A pre-digest ion o f the matr ix , w i t h f ive minutes m ic rowave treatment, had been completed w i t h hydrogen peroxide. Sulfur ic ac id was added w i t h the second stage (5 minutes) m i c r o w a v e treatment. 42 The results were presented i n Figure 20 . The trends o f the two sets were s imi lar , showing that phosphate release increased w i t h samples o f higher T S concentration. The results o f Set 1 as shown i n F igure 2 0 indicated that phosphate release decreased as temperature was increased f rom 6 0 ° C to 9 0 ° C . One possible explanat ion may be that at 9 0 ° C the l o w soluble phosphate i n the solut ion was due to the presence o f intermediate products o f polyphosphates. The results o f Set 2 pointed out that phosphate release increased as temperature increased. In Set 1 & Set 2, the m a x i m u m solubi l iza t ion o f phosphate was obtained at 170°C. 250 o 0 -I , 1 , , : 1 0 30 60 90 120 150 180 Temperature (°C) —»-Set 1*: Sample 1 (TS=1.57%) - " - S e t 1*: Sample 2 (TS=1.36%) —A—Set 1*: Sample 3 (TS=0.93%) - o - Set 2* :Sample 1 (TS=1.57%) - • - Set 2*: Sample 2 (TS=1.36%) - A - Set 2*: Sample 3(TS=0.93%)' * Set 1: Is' stage with H£04 added, 2nd stage with H202 added; Set 2: Is' stage with H202 added, 2nd stage with HiSOj added. Figure 20. Relationship of temperature on ortho-P concentrations in dairy manure with combined H2S04/H202/microwave process (mean of twelve observations). Resul ts as shown i n Figure 2 0 indicated that i n Set 1 at 170°C, 191.7 m g / L o f phosphate was released f rom Sample 1, indicat ing that 8 4 . 4 % o f T P was released; 178.1 m g / L o f phosphate was released f rom Sample 2 , indica t ing that 7 8 . 4 % o f T P was released; 39 .9 m g / L o f phosphate was released f rom Sample 3, ind ica t ing that 17 .6% o f T P was released. 43 Therefore, i n Set 1 the phosphate recovery rates o f Sample 1, Sample 2, and Sample 3 were 9 4 . 3 % , 89 .6%, and 2 7 . 7 % respectively. In Set 2 at 1 7 0 ° C , 197.6 m g / L o f phosphate was released f rom Sample 1, indica t ing that 8 7 . 0 % o f T P was released; 174.3 m g / L o f phosphate was released f rom Sample 2, ind ica t ing that 76 .7% o f T P was released; 34.7 m g / L o f phosphate was released from Sample 3, ind ica t ing that 15.3 % o f T P was released. Therefore, i n Set 2 the phosphate recovery rates o f Sample 1, Sample 2, and Sample 3 were 96 .9%, 87 .9%, and 25 .4% respectively. The results o f Set 1 were summar ized i n the Table E - 4 o f A p p e n d i x E , and the results o f Set 2 were summar ized i n the Tab le E - 5 o f A p p e n d i x E . Resul ts o f both sets showed that phosphate release increased as T S concentrat ion o f sample increased. It was reported that up to 6 5 % o f phosphorus i n an imal manures is i n an organic fo rm, and most o f the phosphorus is i n the so l id fraction (Barnett, 1994). The results o f Set 1 and Set 2 were very s imi la r , indica t ing that sulfuric ac id and hydrogen peroxide had same o x i d i z i n g power , and they both c o u l d complete the digest ion. Theore t ica l ly hydrogen peroxide due to its o x i d i z i n g power should be added after p r imary sulfuric a c i d has completed a pre-digestion o f the matr ix , and then hydrogen peroxide can complete the digest ion safely. Rea l i s t i ca l ly , the chemica ls (sulfuric ac id and hydrogen peroxide) addi t ion sequence doesn' t rea l ly matter at a l l , but i n considerat ion o f foam format ion, it was recommended that sulfuric ac id should be added first for p r imary digest ion, and us ing hydrogen peroxide after the p r imary digest ion o f organic matter is completed is one w a y to a v o i d potent ial ly v io lent reactions. 5.3 Results Summary The results o f l i q u i d dairy manure characterization and the results o f pre-treatment processes are a l l summar ized i n Table 2. To ta l sol ids , ortho-P, and T P concentrations var ied dur ing the seven-month study per iod . T h e results as s h o w n i n T a b l e 2 indicated that the A O P process by us ing f k C V m i c r o w a v e d idn ' t facilitate the phosphorus release f rom dai ry manure even w i t h h igh temperature. O n l y 17.4% o f T P c o u l d be released at 44 heating t ime o f f ive minutes at 1 7 0 ° C , compared to 25.8 % o f T P release at 6 0 ° C w i t h f ive minutes heating t ime. The ox ida t ion induced by H2O2 at ambient temperature ( ~ 2 0 ° C ) c o u l d enhance the release o f phosphorus from dai ry manure w i t h the need o f a longer react ion t ime. M o r e than 6 6 % o f T P c o u l d be released at ambient temperature w i t h eighty-hour react ion per iod . T h i s indicated that higher phosphate recovery o f dai ry manure w i t h the addi t ion o f H2O2 w i l l achieve at lower temperature. Table 2. Results summary of manure p characterization and pre-treatment processes. Manure P Characterization Study material pH Total Soilds 0-P0 4 TP (%) (mg P/L) (mg/L) Liquid dairy manure 7.6-8.2 1.28-1.60 16.5±0.5 - 39.5±2.5 117.5±12.2~ 227.2±9.1 Manure Pre-Treatment Processes Appartus Temperature Chemical Reaction/Heating Ortho-P P Recovery <°C) Time (mins) Released (%) (%) N/A 20 H 20 2 4800 66.5 83.1 N/A 20 H 2S0 4/H 20 2 0 73.1 85.3 N/A 20 H 2S0 4/H 20 2 2940 81.0 93.2 Microwave 170 N/A 5 13.4 35.0 Microwave 60 H 20 2 5 25.8 40.3 Microwave 170 H 20 2 5 17.4 32.0 Microwave 170 H 2S0 4 5 82.2 91.4 Microwave 170 H 2S0 4/H 20 2 10 84.4 94.3 The combined H2S0 4/H202/microwave process c o u l d help release phosphate into the solu t ion from dairy manure and also provide the release o f a m a x i m u m amount o f bound phosphorus at 170°C . M o r e than 8 2 % o f T P c o u l d be released after p r imary sulfuric ac id digest ion w i t h f ive-minute heating t ime. H2O2 c o u l d complete the digest ion after p r imary ac id digest ion, and more than 8 6 % o f T P c o u l d be released at 1 7 0 ° C , representing more that 9 6 % o f total phosphate. The addi t ion o f hydrogen peroxide after the p r imary ac id digest ion o f organic matter is completed is one w a y to a v o i d potential ly v io lent reactions. The addi t ion o f combined H2SO4/H2O2 facilitates the phosphate release from dai ry manure at ambient temperature efficiently and s imp ly , and no heating is required. M o r e 45 than 8 0 % o f T P c o u l d be released f rom dai ry manure at ambient temperature ( ~ 2 0 ° C ) , result ing i n at least 9 3 % o f phosphate recovery. The results also showed that heating treatment alone does not release ortho-P from dai ry manure, because i t ' s insufficient to break d o w n the chemica l chains i n dai ry manure b y app ly ing heat on ly . T h e combined ^ S C V m i c r o w a v e and the combined H2S04/H202/mivrowave both can achieve more than 9 0 % o f phosphate recovery. T h e o n l y difference is that the latter combina t ion can m i n i m i z e the potential safety hazards because the hydrogen peroxide can complete the digest ion. 46 6 CONCLUSIONS M a n u r e pre-treatment processes can facilitate phosphorus release f rom the dai ry manure. These innovat ive and efficient manure pre-treatment processes have the potential not o n l y for the development o f a s imple manure treatment process, but also facilitate phosphorus recovery f rom manure. The released phosphorus can be recovered as struvite fert i l izer v i a the crys ta l l iza t ion. The major p rob lem i n recover ing phosphate i n the form o f struvite is that the struvite crys ta l l iza t ion chemistry is extremely c o m p l e x and h igh ly dependent o n loca l condi t ions (Andrade and S c h u i l l i n g , 2001) . Techn ica l knowledge o n crys ta l l iza t ion reactor designs and op t im ized operating condi t ions i s not fu l ly developed. H o w e v e r , it is k n o w n the p H and temperature are important operating parameters i n struvite crys ta l l iza t ion . T h e extraction o f phosphorus f rom manure is the k e y step to achieve better results i n recover ing phosphate v i a struvite. Therefore, it is very important to develop manure pre-treatment method to op t imize the phosphorus release. T h e recovery o f phosphorus f rom agricul tural wastes w i l l enable the industry to replace a non-renewable resource w i t h a sustainable recyc led r aw mater ial . Af te r manure pre-treatment processes, an average o f 8 0 - 9 0 % o f manure phosphorus can be rendered into the solut ion. In the manure pre-treatment processes, the experiment o f manure w i t h H2O2 addi t ion and the experiment o f manure w i t h the combined H2SO4/H2O2 addi t ion were both conducted w i t h and wi thout m ic rowave treatments. The s imi l a r results indicated that the oxidat ions induced b y the addi t ion o f the combined H2SO4/H2O2 w i t h and wi thout m i c r o w a v e treatments both facilitate phosphorus release f rom dairy manure. The ox ida t ion wi thout mic rowave treatment needed a longer react ion t ime (~ 49 hours) to complete the react ion at ambient temperature, w h i l e o n l y ten minutes were needed b y the ox ida t ion w i t h m ic rowave treatments at 170°C to complete the react ion. The experiments o f manure w i t h and wi thout sulfuric ac id addi t ion were conducted w i t h m i c r o w a v e treatments, and the results showed that chemica l addit ions c o u l d facilitate phosphorus release f rom dai ry manure, w h i l e heating treatment alone c o u l d not ease phosphorus release. 47 RECOMMENDATIONS FOR FUTURE STUDIES • Apparen t ly , the increased d i lu t ion magni f ied the interferences o f ortho-P concentration. T h e posi t ive interferences caused b y u n k n o w n compounds i n the dairy manure cou ldn ' t be e l iminated i n this study, because the enzyme, composi tes , pathways and kinet ics o f P c y c l i n g i n dai ry manures are p o o r l y understood. Therefore, the study o n ortho-P interferences should be conducted i n the future. • The challenges to scale up phosphorus release f rom manure into commerc i a l operations inc lude: 1) Cos t est imation for the reactor and the energy required for the pretreatment process; 2) A d d i t i o n a l free board i n the reactor and chemica ls required for the control o f the massive foam; 3) Assurance o f the eff ic iency, the stabil i ty, and the safety o f reactions i n v o l v e d i n the pretreatment process. 48 REFERENCES A b e l s o n , P . H . (1999) A potential phosphate cr is is . Science, 283, pp. 2015. A P H A . (1998) Standard Methods for the Examination of Water and Wastewater. 1 9 t h E d i t i o n . A m e r i c a n P u b l i c health Assoc i a t i on , Wash ing ton , D . C . . Andrade , A . , and S c h u i l i n g , R . D . (2001) T h e chemistry o f struvite crys ta l l iza t ion . Mineralogical Journal (Ukraine), 23, pp. 37-46. A S A E Standards (2003) Manure Production and Characteristics. A m . Soc . A g r i c . E n g . , St. Joseph, M i c h i g a n , A S A E Data D384.1. A z e v e d o , J . , and Stout, P . R . (1974) Farm animal manures: A review of their role in the agricultural environment. C a l i f o r n i a A g r i c u l t u r a l E x p . St. Ex tens ion Service , Manual 44. Barnett, G . M . , (1994) Phosphorus forms i n an imal manure. Bioresour. Technol, 49, pp. 139-147. Bat t i s toni , P . , Fava , G . , Pavan , P . , et a l . (1997) Phosphate r emova l i n anaerobic l iquors b y struvite crys ta l l iza t ion wi thout addi t ion o f chemicals : P re l imina ry results. Water Res., 31 (11), pp. 2925-2929. Bat t is toni , P . , Pavan , P . , Pr isc iandaro, M . , et a l . (2000) Struvite crys ta l l iza t ion: A feasible and rel iable w a y to f ix phosphorus i n anaerobic supernatants. Water Res., 34 (11), pp. 3033-3041. Becker , P . (1989) Phosphates and phosphoric Acid. Second E d i t i o n . M . Dekke r , N e w Y o r k . Benson , R . L . , M c k e l v i e , I .D . , Hart , B . T . , and H a m i l t o n , I .C . (1994) Dete rmina t ion o f total phosphorus i n waters and wastewaters b y onl ine mic rowave- induced digest ion and f low-in jec t ion analysis. Anal. Chim. Acta, 291 (3), pp. 233-242. B o c k , R . (1979) A Handbook of Decomposition Methods in Analytical Chemistry. translated [from the German] and revised b y M a r r , I. L . , 1st ed.; John W i l e y and Sons, N e w Y o r k . Brett , S., G u y , L M o r s e , G K and Lester , J . N . (1997) Phosphorus Removal and Recovery Technologies. Selper L t d . , L o n d o n , pp. 142. 49 B r i s b i n , P . E . (1995) Agricultural Nutrient Management in the Lower Fraser Valley. Component Project of Management of Livestock and Poultry Manures in the Lower Fraser Valley. Report 4. Prepared for: B C M i n i s t r y o f Env i ronment , Lands and Parks , Env i ronment Canada - Fraser R i v e r A c t i o n P l a n , B C M i n i s t r y o f Agr icu l tu re , Fisheries and F o o d and Fisheries and Oceans - Fraser R i v e r A c t i o n P lan . Vancouve r , B . C . DOE FRAP 1995-27. Centre Europeen d 'Etudes des Polyphosphates ( C E E P ) . Recovery of Phosphates for Recycling. C E F I C (European C h e m i c a l Industry C o u n c i l ) A v e n u e E . V a n Nieuwenhuyse 4, B te 2, B l 160, B ruxe l l e s , B e l g i u m , pp. 13. Chardon , W . J . and Oenema, O . (1995) Leaching of Dissolved organically bound Phosphorus. D L O Research Institute for A g r o b i o l o g y and S o i l Fer t i l i ty ( A B -D L O ) : Wagen ingen . Chardon , W . J . , Oenema, O . , de l Cas t i lho , P . and V r i e s e m a , R . (1997) Organ ic phosphorus solutions and leachates f rom soils treated w i t h an ima l slurries. J. Environ. Qua!., 26, pp. 372-378. D a n i e l , I .C . , Sharpley, A . N . and L e m u n y o n , J . L . (1998) A g r i c u l t u r a l phosphorus and eutrophication: A s y m p o s i u m overv iew. J. Environ. Qual, 27, pp. 251-257. Dr ive r , J . , L i j m b a c h , D . , and Steen, I. (1999) W h y recover phosphorus for r ecyc l ing , and h o w ? . Environ. Technol, 20, pp. 651-662. Durrant , A . E . , Sc r imshaw, M . D . , Stratful, I., and Lester , J . N . (1999) R e v i e w o f the feasibi l i ty i f recover ing phosphate f rom wastewater for use as a r a w material b y the phosphate industry. Environ. Technol, 20 (7), pp. 749-758. E b i n a , J . , Tsutsui , T . , and Sh i ra i , T . (1983) Simultaneous determination o f total ni t rogen and total phosphorus i n water us ing peroxodisulfate ox ida t ion . Water Res., 17 (12), pp. 1721-1726. E l l i s , B . E . , and M i l e s , G . P . (2001) One for a l l . Science, 293 (5529), pp. 428-428. F o y , R . H . and Withers , P . J . A . (1995) T h e contr ibut ion o f agr icul tural phosphorus to eutrophication. The Fert. Soc. Proc, 365, pp. 1-32. Greaves , J . , Hobbes , P . , C h a d w i c k , D . , and Haygar th , P . (1999) Prospects for the recovery o f phosphorus f rom an imal manures: A R e v i e w . Environ.Technol, 20, pp. 697-708. 50 Hayes , V . W . , and Swenson , M . J . (1970) Minerals. In Duke's physiology of domestic animals. E d i t e d by M J . Swenson . C o r n e l l U n i v . Press, Ithaca, N . Y . , pp. 663-696. Haygar th , P . M . , Jarvis , S . C , Chapman , P . , and S m i t h , R . V . (1998) Phosphorus budgets for two contrasting grassland farming systems i n the U K . Soil Use Manage., 14, pp. 1-9. Haygar th , P . M . , and Sharpley, A . N . (2000) T e r m i n o l o g y for phosphorus transfer. J. Environ. Qual, 29 (1), pp . 10-15. Jackson, M . L . (1958) Soil Chemical Analysis. P ren t i ce -Ha l l , Inc., E n g l e w o o d C l i f f s , N . J . K i n g s t o n , H . M . , and Jassie, L . B . (1988) M i c r o w a v e ac id sample decompos i t ion for elemental analysis . J. Res. Natl. Bur. Stand., 93 (3), pp. 269-274. K l e i n m a n , P . J . A . , Sharpley, A . N . , W o l f , A . M . , Beeg le , D . B . , and M o o r e , P . A . (2002) M e a s u r i n g water-extractable phosphorus i n manure as an indicator o f phosphorus i n runoff. Soil Sci. Soc. Am. J., 66 (6), pp. 2009-2015. K u r o k a , A . , Tak iguach i , N . , Gotanda, T . , N o m u r a , K . , K a t o , J . , Ikeda, T . , and Ohtake, H . (2002) A s imple method to release polyphosphate from activated sludge for phosphorus reuse and recyc l ing . Biotech. & Bioengng, 78 (3), pp. 333- 338. Leinweber , P . , Haumaier , L . , and Z e c h , W . (1997) Sequential extractions and 3 1 P - N M R spectroscopy o f phosphorus forms i n an imal manures, who le soi ls and part icle-size separates f rom a densely populated l ives tock area i n Nor thwes t Germany . Biol. Fertil. Soils, 25, pp. 89-94. M a q u e d a , C , Rodr iguez , J . L . P . , and Lebrato , J . (1994) Study o f struvite precipi ta t ion i n anaerobic digesters. Water Res., 28 (2), pp. 411-416. M o m b e r g , G . A . , and Oe l le rmann , R . A . (1992) The remova l o f phosphate b y hydroxyapati te and struvite crys ta l l iza t ion i n south- A f r i c a . Wat. Sci. Technol., 26 (5-6), pp. 987-996. M o r s e , D . , H e a d , H . H . , W i l c o x , C . J . , V a n H o r n , H . H . , H i s s e m , C D . , and H a r r i , B . Jr. (1992) Effects o f concentrat ion o f dietary phosphorus o n amount and route o f excret ion. J. Dairy Sci., 75, pp. 3039-3049. M o s s , B . (1996) A land awash w i t h nutrients - the p rob lem o f eutrophication. Chem. Ind., 11, pp. 407-411 . 51 M u n c h , E . V . , and Bar r , K . (2001) Con t ro l l ed struvite crysta l l isa t ion for r emov ing phosphorus f rom anaerobic digester sidestreams. Water Res., 35 (1), pp. 151-159. M u r p h y , J . and R i l e y , J .P . (1962) A mod i f i ed single solu t ion method for the determination o f phosphate i n natural waters. Anal. Chim. Acta., 27, pp. 31-36. N e l s o n , N . O . , M i k k e l s e n , R . L . , and Hesterberg, D . L . (2003) Struvite precipi ta t ion i n anaerobic swine lagoon l i q u i d : effect o f p H and M g : P ratio and determination o f rate constant. Bioresour. Technol, 89 (3), pp. 229-236. Ormaza -Gonza l ez , F . I . , and Statham, P . J . (1996) A compar i son o f methods for the determinat ion o f d i sso lved and particulate phosphorus i n natural waters. Water Res., 30, pp. 2739-2747. Peperzak, P . , C a l d w e l l , A . G . , H u n z i k e r , R . R . , and B l a c k , C A . (1959) Phosphorus fractions i n manure. Soil Sci, 87, pp. 293-302. Sapach, R . , and Vi ra raghavan , T . (1997). A n introduct ion to the use o f hydrogen peroxide and ul t raviolet radiat ion: A n advanced ox ida t ion process, J. Environ. Sci. Health, A, 32 (8), pp. 2355-2366. Sanz, J . , Lombrana , J . L , D e L u i s , A . M . , V e r o n a , F . , and Ortueta, M . (2002). Study and compar i son o f advanced ox ida t ion techniques i n the treatment o f contaminated effluents. AFINIDAD, 59 (501), pp. 542-552. Schindler , D . W . (1977) E v o l u t i o n o f phosphorus l imi ta t ion i n lakes. Science, 195, pp. 260-262. Schreier, F L , Bestbier , R . , and Derksen , G . (2003) Agricultural Nutrient Management Trends in the Lower Fraser Valley, BC. (electronic source). Institute for Resources and Env i ronment ( I R E ) , U B C . S c h u i l i n g , R . D . , and Andrade , A . (1999) R e c o v e r y o f Struvite f rom C a l f M a n u r e . Environ. Technol, 20 (7), pp. 765-768. Sharpley, A . N . , Chapra , S . C , W e d e p o h l , R . , and S i m s , J .T . (1994) M a n a g i n g agricul tural phosphorus for the protect ion o f surface waters: issue and options. J. Environ. £ W . , 2 3 , p p . 437-451. Statistics Canada, (2001) L i v e s t o c k Concent ra t ion - where are they?. V I S T A o n the A g r i - F o o d Industry and the F a r m C o m m u n i t y , Catalogue No. 21-004-XIE. 52 Stratful, I., Brett , S., Sc r imshaw, M . B . , et a l . (1999) B i o l o g i c a l phosphorus r emova l , its ro le i n phosphorus r ecyc l ing . Environ, Technol, 20 (7), pp. 681-695. T a i z , L . and Zeiger , E . (1991) Plant Physiology. E . B . B r a d y (ed.), B e n j a m i n / C u m m i n g s P u b l . C o . Inc.: R e d w o o d C a l i f , pp. 565. T o m l i n s o n , A . P . , Powers , W . J . , V a n H o e n , H . H . , Nordstedt , R . A . , and W i l c o x , C . J . (1996) Die tary protein effects o n ni t rogen excret ion and manure characteristics o f lactating cows . Trans. ASAE, 39 (4), pp. 1441-1448. Tunay , O . , K a b d a s l i , I., and G u n , O . (2004) Sequencing batch reactor treatment o f leather tanning industry wastewaters. Fresenius Environ. Bull, 13 (10), pp. 945-950. U . S . Env i ronmenta l Protect ion A g e n c y (1996) Env i ronmen ta l indicators o f water qual i ty i n the U n i t e d States. EPA 841-R-96-002. U . S . Env i ronmenta l Protect ion A g e n c y (1999) P re l imina ry Da ta Summary : Feedlots Po in t Source Category Study. EPA-821-R-99-002. Vetter , H . and Steffens, G . (1980) Phosphorus accumula t ion i n so i l profi les and phosphorus losses after the appl ica t ion o f an imal manures. In: Phosphorus in Sewage Sludge and Animal Waste Slurries.: D . R e i d e l Pub l i sh ing , Gron ingen , T h e Netherlands, pp. 309-327. Whetstone, G . A . , Parker , H . W . , and W e l l s , D . M . (1974) Study of current and proposed practices in animal waste management. U . S . Env i ronmen ta l Protect ion A g e n c y . EPA 430/9-74-003. W h i t e , R . K . , and Forster, D . L . (1978) Evaluation and economic analysis of livestock animal waste systems. U . S . Env i ronmen ta l Protect ion A g e n c y . EPA 600/2-78-102. Z d y b i e w s k a , M . W . , and K u l a , B . (1991) R e m o v a l o f a m m o n i a ni trogen by the precipi ta t ion method, o n the example o f some selected waste-waters. Water Sci. Technol, 24 (7), pp . 229-234. 53 A P P E N D I X A C H A R A C T E R I S T I C S O F D A I R Y M A N U R E Table A-1. pH & total solids in liquid dairy manure. Study Material Manure/DI water Manure/DI water Manure/DI water Manure/DI water (v/v) = 1:0 (v/v) = 1:1 (v/v) = 1:4 (v/v) = 1:9 Sampling Month pH Total Solids) %) pH Total Solids( %) pH Total Solids( %) pH Total Solids(%) Jun-2004 7.60 1.28 7.59 0.62 7.70 0.25 7.65 0.11 Jul-2004 7.86 1.20 7.96 0.61 8.02 0.23 8.00 0.12 Aug-2004 7.67 1.33 7.58 0.64 7.61 0.28 7.65 0.12 Sep-2004 7.68 1.40 7.76 0.66 7.60 0.28 7.70 0.13 Oct-2004 7.75 1.45 7.86 0.72 7.80 0.31 7.73 0.13 Nov-2004 7.99 1.50 8.15 0.69 8.16 0.29 8.21 0.15 Dec-2004 8.00 1.60 8.05 0.78 8.10 0.31 8.11 0.15 Table A-2. Total phosphate concentration in liquid dairy manure. Study Material Manure/DI water Manure/DI water Manure/DI water Mean (v/v) = 1:1 (v/v) = 1:4 (v/v) = 1:9 Sampling Month TP STDEV TP STDEV TP STDEV TP STDEV Unit Jun-2004 103.9 3.9 121.4 11.4 127.4 13.1 117.5 12.2 mg/L Jul-2004 117.8 8.4 131.7 17.5 132.4 16.0 127.3 8.2 mg/L Aug-2004 135.6 4.3 142.9 1.7 144.2 1.4 140.9 4.7 mg/L Sep-2004 156.1 11.0 164.3 7.3 160.7 8.4 162.3 4.1 mg/L Oct-2004 172.5 3.6 183.0 4.7 185.9 7.0 180.5 7.1 mg/L Nov-2004 209.8 1.5 197.5 9.7 211.8 7.2 206.4 7.8 mg/L Dec-2004 216.8 5.3 233.4 17.4 231.5 18.8 227.2 9.1 mg/L Table A-3. Ortho-P concentration in liquid dairy manure. Study Material Manure/DI water Manure/DI water Manure/DI water Manure/DI water (v/v) = 1:0 (v/v) = 1:1 (v/v) = 1:4 (v/v) = 1:9 SET# Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 1 16.5 0.5 45.5 2.4 89.6 0.8 114.3 0.2 mg P/L 2 23.0 1.5 41.3 0.7 121.2 12.8 127.5 1.6 mg P/L 3 22.6 0.2 39.0 0.4 94.9 1.2 116.9 0.7 mgP/L 4 23.1 0.2 38.7 0.3 93.7 0.7 96.6 0.3 mg P/L 5 21.1 0.7 51.1 4.7 96.4 0.5 105.8 3.9 mgP/L 6 24.9 0.1 38.3 2.0 96.6 0.1 110.2 5.6 mg P/L 7 30.8 0.8 51.3 2.7 96.2 0.2 110.4 6.2 mg P/L 8 39.5 2.4 58.2 3.8 106.2 0.5 115.8 8.1 mg P/L 9 38.8 0.2 68.2 5.0 128.3 0.7 138.8 3.8 mg P/L 10 32.7 1.2 49.2 0.7 85.6 2.1 111.0 7.3 mg P/L Mean 27.3 7.8 48.1 9.7 100.9 13.7 114.7 11.6 mgP/L 5 4 APPENDIX B ORTHO-P STANDARD ADDITION IN DAIRY MANURE Table B-1. Extent of recovery of the added quantity of ortho-P standards. Standard addition con. 0 ppm (Control) 25 ppm 50 ppm 100 ppm Manure/DI water(v/v) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit mg P/L mgP/L mgP/L mgP/L Table B-2. The data comparison of ortho-P standard addition. 1:0 25.9 1.2 30.9 4.9 44.3 1.9 75.4 1.4 1:1 52.3 2.3 28.3 3.3 38.2 1.1 71.5 13.3 1:4 101.0 1.0 22.9 1.4 35.5 0.2 61.0 0.7 1:9 123.9 0.9 18.7 0.9 43.4 0.3 57.1 1.8 Standard addition con. 25 ppm 50 ppm 100 ppm Ortho-P con. Expected Difference Expected Difference Expected Difference Unit Manure/DI water(v/v) 1:0 25.4 5.5 37.9 6.3 62.9 12.5 mg P/L 1:1 38.7 -10.4 51.2 -13.0 76.2 -4.7 mgP/L 1:4 63.0 -40.1 75.5 -40.0 100.5 -39.5 mgP/L 1:9 74.4 -55.7 86.9 -43.5 111.9 -54.8 mgP/L Expected (100 % recovery) ortho-P concentration — x Concentration of Control set U J + — x Concentration of Standard addition | 2 J Difference of ortho-P concentration = expected ortho-P concentration - extent of ortho-P recovery 55 APPENDIX C INTERFERENCE ELIMINATION TESTS Table C-1. Decolonization of dairy manure sample by activated charcoal. Chemicals added Nothing Activated charcoal Activated charcoal Reaction Time (Control) 5 minutes 8 hours Manure/DI water (v/v) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 1:0 23.4 1.4 13.3 1.5 8.4 0.6 mg P/L 1:1 45.8 5.1 34.1 0.0 9.7 1.8 mg P/L 1:4 100.6 1.1 82.8 1.6 59.6 4.8 mg P/L 1i9 97.7 1.3 81.9 1.5 60.0 5.5 mg P/L Table C-2. Ortho-P concentration of dairy manure extracted with NaHCOa/HCI. Chemicals added Nothing (Control) NaHCQ 3 HCI Manure/DI water(v/v) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 1:0 21.1 0.7 39.9 2.5 41.7 7.7 mg P/L 1:1 51.1 4.7 73.1 5.1 59.1 2.9 mg P/L 1:4 96.4 0.5 173.0 6.6 119.0 7.4 mg P/L 1 * 105.8 3.9 173.5 13.3 109.8 5.7 mg P/L Table C-3. Ortho-P concentration in the solution extracted with NaHSOa/HCI+NhUF. Chemicals added Nothing (Control) NaHS0 3 HCI + NH 4F Manure/DI water(v/v) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 1:0 38.8 0.2 50.5 1.5 13.3 1.1 mg P/L 1:1 68.2 5.0 78.7 7.2 65.3 3.9 mg P/L 1:4 128.3 0.7 140.3 3.4 127.3 1.3 mg P/L 1:9 138.8 3.8 148.8 4.3 136.9 7.1 mg P/L Table C-4. Ortho-P concentration in the solution induced by H 2 0 2 . Chemicals added Nothing (Control) H 2 0 2 H 2 0 2 Study material Mixed well manure Mixed well manure Supernatant only Manure/DI water (v/v) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 1:0 32.7 1.2 17.5 2.5 28.4 1.5 mgP/L 1:1 49.2 0.7 30.8 3.6 35.9 1.0 mg P/L 1:4 85.6 2.1 87.8 2.6 85.2 2.3 mgP/L 1:9 111.0 7.3 120.7 5.2 111.1 6.9 mgP/L 56 APPENDIX D ROOM TEMPERATURE PRE-TREATMENT PROCESS Table D-1. Ortho-P concentration in the solution with manure/H 20 2 (v/v) = 20:1. Run Run 1 Run 2 Mean Reaction Time (hour) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 0 23.0 2.4 24.9 3.6 24.0 1.4 mg P/L 3 41.5 1.3 49.7 2.7 48.6 1.5 mg P/L 5 57.6 4.7 60.3 0.5 58.9 1.9 mg P/L 8 47.5 3.0 49.0 6.3 48.2 1.1 mgP/L 84 44.2 5.3 47.6 2.7 45.9 2.4 mgP/L TP Concentration = 140.9 ± 4.7 mg/L Table D-2. Ortho-P concentration in the solution with manure/H 20 2 (v/v) = 5:1. Run Run 1 Run 2 Mean Reaction Time (hour) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 0 23.8 3.2 23.0 2.5 23.4 0.5 mg P/L 4 30.3 1.2 32.4 0.6 31.3 1.5 mg P/L 6 39.1 6.5 40.6 4.6 39.8 1.1 mg P/L 8 33.5 1.8 35.5 2.2 34.5 1.4 mg P/L 30 45.9 2.7 48.2 0.5 47.1 1.6 mg P/L 35 48.8 4.5 51.3 0.4 50.1 1.8 mg P/L 60 119.9 0.8 116.0 4.7 117.9 2.7 mgP/L 80 113.7 7.8 120.4 2.9 117.1 4.8 mg P/L TP Concentration = 140.9 ± 4.7mg/L Table D-3. Ortho-P concentration in the solution induced by combined H 2 S04/H 2 0 2 . Run Run 1 Run 2 Mean Reaction Time (hour) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 0.0 197.5 4.1 189.8 2.0 193.6 5.5 mg P/L 2.5 204.0 4.7 195.8 0.9 199.9 5.8 mgP/L 5.0 201.5 4.3 195.2 5.4 198.4 4.4 mgP/L 49.0 213.6 1.2 209.9 7.3 211.7 2.6 mgP/L Ortho-P concentration of original manure sample = 27.7 ± 0.5 mg P/L TP Concentration = 227.24 ± 9.1 mg/L 57 APPENDIX E MICROWAVE PRE-TREATMENT PROCESS Table E-1. Ortho-P concentration in the solution induced by one stage microwave treatment without chemical addition. Sample ID Sample 1 Sample 2 Sample 3 Sample 4 Manure/DI water Manure/DI water Manure/DI water Manure/DI water (v/v) = 1:0 (v/v) = 1:1 (v/v) = 1:4 (v/v) = 1:9 TemperaturefC) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit 0 25.3 1.3 49.9 1.7 77.2 2.2 91.9 4.6 mg P/L 60 33.0 2.1 51.8 6.8 78.7 6.3 92.5 6.2 mg P/L 90 20.1 1.4 24.9 6.4 37.4 4.4 68.2 7.6 mgP/L 120 22.5 6.5 25.5 2.1 21.9 1.4 31.1 3.7 mg P/L 170 41.1 5.5 45.1 4.6 11.5 2.5 19.5 1.3 mgP/L TP concentration = 117.5 ± 12.2mg/L 5 8 Table E-2. Ortho-P concentration in the solution induced by combined H 20 2/one stage microwave treatment. SET ID SET 1 SET 2 SET3 Manure/H 20 2 ratio Manure/H 20 2 Manure/H 20 2 Manure/H 20 2 (v/v) = 20:1 (v/v) = 10:1 (v/v) = 5:1 Temperature(°C) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit Run 1 0 15.3 2.6 15.3 2.6 15.3 2.6 mg P/L 60 30.8 4.8 40.2 7.1 46.3 4.6 mg P/L 90 25.4 6.6 35.9 3.1 41.5 2.4 mgP/L 120 24.0 2.2 29.5 4.1 35.3 3.1 mg P/L 170 23.6 0.4 30.1 4.9 37.0 2.3 mg P/L Run 2 0 17.5 3.2 17.5 3.2 17.5 3.2 mg P/L 60 32.9 1.7 40.5 3.1 48.4 1.5 mgP/L 90 28.3 1.7 33.7 2.1 43.6 3.1 mg P/L 120 25.4 2.0 35.3 2.7 39.6 3.3 mg P/L 170 26.6 3.2 34.1 0.3 38.7 0.9 mg P/L Run 3 0 18.5 2.1 18.5 2.1 18.5 2.1 mg P/L 60 35.1 5.8 39.6 2.8 47.5 5.0 mg P/L 90 28.4 2.1 36.1 5.9 44.0 5.7 mgP/L 120 25.0 2.6 32.2 3.3 35.7 2.5 mg P/L 170 26.0 1.7 36.8 3.3 37.1 0.9 mg P/L Mean of three observations 0 17.1 1.7 17.1 1.7 17.1 1.7 mg P/L 60 32.9 2.1 40.1 0.5 47.4 1.1 mgP/L 90 27.3 1.7 35.2 1.4 43.0 1.3 mg P/L 120 24.8 0.7 32.3 2.9 36.9 2.4 mg P/L 170 25.4 1.6 33.6 3.4 37.6 1.0 mg P/L TPconecentration = 117.54 ± 12.2mg/L 59 Table E-3. Ortho-P concentration in the solution induced by combined h^SOVone stage microwave treatment. Sample ID Sample 1 Sample 2 Sample 3 Study material Manure/DI water Manure/DI water Manure/DI water (v/v) = 1:0 (v/v) = 1:4 (v/v) = 1:9 Temperature(°C) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit Run 1 0 15.3 1.3 75.5 5.8 76.5 4.3 mgP/L 60 85.4 2.7 93.2 2.4 94.8 5.1 mg P/L 90 75.0 6.4 86.7 3.6 90.5 5.0 mgP/L 120 78.4 5.8 96.4 2.2 97.2 5.3 mg P/L 150 90.4 2.1 119.1 1.4 124.9 4.4 mgP/L 170 162.5 3.8 153.1 1.8 158.4 4.3 mg P/L Run 2 0 16.9 2.5 76.0 3.7 77.5 3.1 mg P/L 60 84.7 2.1 95.1 4.2 99.1 3.5 mg P/L 90 76.9 3.7 88.4 2.3 94.6 3.0 mg P/L 120 79.0 3.9 95.1 2.0 100.9 6.1 mg P/L 150 93.0 1.4 116.3 2.0 129.0 3.0 mgP/L 170 165.6 2.6 158.4 0.9 160.6 3.2 mg P/L Run 3 0 15.0 3.1 70.5 2.9 75.0 2.6 mg P/L 60 84.8 4.3 90.3 3.8 93.7 6.0 mgP/L 90 70.0 2.9 88.1 1.0 91.5 4.3 mg P/L 120 75.7 1.8 95.5 4.6 99.1 2.7 mg P/L 150 91.4 3.0 123.6 2.6 126.8 2.1 mgP/L 170 167.0 1.9 152.3 2.0 159.7 3.6 mg P/L Mean of three observations 0 16.6 1.0 74.0 3.0 76.3 1.3 mg P/L 60 85.0 0.4 92.9 2.5 95.8 2.8 mgP/L 90 74.0 3.5 87.7 0.9 92.2 2.1 mgP/L 120 77.7 1.7 97.0 1.9 99.0 1.8 mgP/L 150 91.6 1.3 119.7 3.7 126.9 2.1 mg P/L 170 165.0 2.3 154.6 3.3 159.6 1.1 mg P/L TPconecentration = 180.48 ± 7.1 mg/L 60 Table E-4. Ortho-P concentration in the solution induced by combined H2S04 /H202 / two s tages microwave treatment. Sample ID Sample 1 Sample 2 Sample 3 Total Solids (%) TS = 1.57% TS = 1.36% TS = 0.93% Temperature(°C) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit Run 1 0 21.5 1.5 23.9 2.0 23.7 0.4 mgP/L 60 183.3 13.3 165.8 18.0 36.7 7.6 mg P/L 90 183.4 7.5 178.0 4.6 32.7 6.0 mg P/L 120 210.4 8.6 200.5 8.3 50.5 4.9 mg P/L 170 205.2 13.3 203.3 7.2 61.4 4.2 mgP/L Run 2 0 23.5 1.0 27.0 3.1 22.5 1.2 mg P/L 60 186.0 4.8 179.3 4.3 35.6 3.7 mg P/L 90 186.8 4.3 179.5 3.8 37.7 2.9 mgP/L 120 220.3 3.8 201.4 5.9 53.9 5.9 mg P/L 170 223.1 4.7 203.6 4.9 64.6 4.9 mg P/L Mean of two observations 0 22.5 1.4 25.4 2.2 23.1 0.8 mgP/L 60 184.6 1.9 171.1 7.5 36.1 0.8 mgP/L 90 185.1 2.4 178.8 1.1 35.2 3.5 mg P/L 120 215.4 7.0 201.0 0.6 52.2 2.4 mgP/L 170 214.2 2.6 203.5 0.2 63.0 2.2 mgP/L TPconecentration = 227.2 ± 9.1 mg/L 61 Table E-5. Ortho-P concentration in the solution induced by combined H 202/H 2S0 4/two stages microwave treatment. Sample ID Sample 1 Sample 2 Sample 3 Total Solids (%) TS = 1.57% TS = 1.36% TS = 0.93% Temperature(°C) Ortho-P STDEV Ortho-P STDEV Ortho-P STDEV Unit Run 1 0 21.5 1.5 23.9 2.0 23.7 0.4 mgP/L 60 194.2 5.9 169.2 9.6 32.9 9.4 mg P/L 90 222.4 7.8 189.4 9.0 42.1 8.9 mg P/L 120 222.7 5.2 195.4 11.1 52.3 2.5 mg P/L 170 213.3 7.8 192.6 13.4 58.7 3.2 mg P/L Run 2 0 23.5 1.0 27.0 3.1 22.5 1.2 mg P/L 60 197.5 3.3 165.2 5.0 35.7 4.6 mg P/L 90 220.9 5.7 185.7 4.3 43.0 3.1 mgP/L 120 223.5 6.9 203.5 6.5 50.5 4.8 mgP/L 170 227.0 7.0 206.8 5.3 56.9 3.7 mgP/L Mean of two observations 0 22.5 1.4 25.4 2.2 23.1 0.8 mgP/L 60 195.8 2.3 167.2 2.8 34.3 2.0 mgP/L 90 221.7 1.1 187.6 2.6 42.5 0.6 mgP/L 120 223.1 0.6 199.5 5.7 51.4 1.3 mg P/L 170 220.1 9.7 199.7 0.0 57.8 1.2 mg P/L TPconecentration = 227.2 ± 9.1 mg/L 62 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            data-media="{[{embed.selectedMedia}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
https://iiif.library.ubc.ca/presentation/dsp.831.1-0092007/manifest

Comment

Related Items